ISRO ISTRAC Syllabus 2026: Exam Pattern & Selection Process
- Selection: application screening → written test/CBT → skill test → document verification → medical → merit list.
- The written test is objective with 0.33 negative marking per wrong answer.
- The syllabus is post-specific — your trade or subject decides the technical questions.
The ISRO ISTRAC 2026 selection is a multi-stage process built around a post-specific written test. There is no single common syllabus — a Technician-B is tested on their ITI trade, a Technical Assistant on their diploma engineering branch, and a Scientific Assistant on their B.Sc subject. This article lays out the full selection process stage by stage, the written test pattern (including negative marking), the post-wise technical syllabus, the skill test, and exactly how the final merit is decided, so you know precisely what to prepare. Always confirm the detailed syllabus for your post against the official ISRO notification.
👉 ISRO ISTRAC Previous Year Papers — see the real question pattern and difficulty before you start preparing.
The selection process — stage by stage
| Stage | What happens |
|---|---|
| Application screening | Eligibility and qualification check against the post requirements |
| Written Test / CBT | Objective test on the post-specific technical syllabus, with negative marking |
| Skill Test / Trade Test | Practical/skill assessment for the relevant post (qualifying or weighted as per notice) |
| Document Verification | Originals checked — qualification, age, category, experience |
| Medical Examination | Fitness as per ISRO standards |
| Final Merit List | Based on written test (and skill test where applicable) performance |
The written test is the gate that decides who moves forward, so it deserves the bulk of your preparation. The skill or trade test that follows confirms you can actually do the hands-on work of the post. Document verification and the medical are clearance stages — you must meet every requirement on paper and be medically fit. The final merit is built primarily on your written-test score (with the skill test weighted as specified in the notification).
Written test / CBT — the exam pattern
The written test is an objective, multiple-choice examination. The defining features you must plan around are:
- Format: objective multiple-choice questions (MCQs).
- Negative marking: 0.33 marks deducted for every wrong answer — guessing blindly costs you.
- Content: weighted heavily toward your post-specific technical subject.
- Standard: at the level of the qualifying qualification (ITI/diploma/degree) for the post.
The 0.33 negative marking is the single most important strategic fact: because a wrong answer costs you a third of a mark, you should answer questions you are reasonably sure of and avoid wild guesses on questions you have no idea about. Educated elimination (narrowing four options down to two) usually still favours attempting; a complete blind guess does not. Accuracy beats reckless attempt count in this exam.
The post-wise technical syllabus
Because ISRO recruits across very different posts, the technical syllabus is decided by your post. Map your preparation to the right column:
| Post | Technical syllabus focus |
|---|---|
| Technician-B | Your ITI trade theory and practical (Electronics, Electrical, Fitter, Mechanic, etc.) |
| Draughtsman-B | Drawing/draughtsmanship theory and practice of your trade |
| Technical Assistant | Your diploma engineering branch core subjects |
| Scientific Assistant | Your B.Sc subject (Physics, Chemistry, Electronics, CS, etc.) |
| Library Assistant-A | Library and Information Science (Master’s level) |
For trade and diploma posts, the questions test the core theory and applied knowledge of your discipline — the same fundamentals you studied to earn the qualification, asked at a practical, application-oriented level. For Scientific Assistant, expect degree-level questions in your science subject. There may also be a portion of general/aptitude questions, but the technical subject carries the weight, so deep command of your own discipline is what wins this exam.
How to prepare effectively
Start by downloading the official notification and noting the exact syllabus and post for which you are applying. Then build your study around three things: first, revise the core theory of your trade/branch/subject from your own ITI, diploma or degree material — this is the highest-return effort; second, practise objective MCQs in your subject to build speed and accuracy under the negative-marking regime; third, work through previous ISRO papers and similar technical-exam papers to understand the question style and difficulty. Because the test rewards applied understanding rather than rote memory, focus on concepts you can reason with, not just facts you have memorised.
👉 ISRO ISTRAC 2026 — Apply Online — official notification, post-wise syllabus and the apply link.
The skill test / trade test
Candidates who clear the written test are called for a skill or trade test relevant to their post — a practical assessment that confirms you can perform the hands-on work. For technical and draughtsman posts this is a trade/practical test; the notification specifies whether it is qualifying or carries weight in the final merit. Prepare for it the way you would for a practical exam in your trade: revise the hands-on procedures, safety, measurements and standard practices of your discipline. The skill test is not a formality — it is ISRO confirming that, beyond theory, you can actually do the job.
What no other site tells you
The single most useful thing to understand about the ISRO ISTRAC exam is that it is a post-specific technical test, not a general competitive exam. There is no giant general-knowledge syllabus to mug up — your entire advantage comes from deep command of your own trade, diploma branch or science subject. That is good news: the syllabus is exactly the subject you already studied, so focused revision of your discipline plus disciplined MCQ practice under the 0.33 negative-marking rule is the winning formula. Two practical tips that pages rarely give: respect the negative marking (accuracy over reckless attempts), and do not neglect the skill/trade test — strong candidates sometimes ace the written test and then underprepare the practical, which is where the post is finally confirmed. Prepare both, and an ISRO technical post is a genuinely winnable target.
Frequently Asked Questions
What is the ISRO ISTRAC selection process?
Application screening, then a written test/CBT on your post-specific technical syllabus, a skill/trade test, document verification, a medical examination, and the final merit list.
Is there negative marking in the ISRO ISTRAC exam?
Yes — 0.33 marks are deducted for every wrong answer in the objective written test, so accuracy matters and blind guessing is costly.
What is the syllabus for the written test?
It is post-specific: your ITI trade (Technician-B), drawing trade (Draughtsman-B), diploma engineering branch (Technical Assistant), or B.Sc subject (Scientific Assistant), at the level of that qualification.
Is there a skill test?
Yes. Candidates who clear the written test face a skill/trade test relevant to their post, which is qualifying or weighted as specified in the notification.
Is there a general knowledge paper?
The exam is weighted toward your technical subject; there may be a small general/aptitude portion, but the technical discipline carries the weight.
How should I prepare?
Revise the core theory of your trade/branch/subject, practise MCQs for speed and accuracy under the negative-marking rule, and work through previous papers, then prepare the skill test like a practical exam.
A practical study timeline for the written test
Knowing the syllabus is one thing; having a plan to cover it is another. A sensible approach is to split your preparation into three phases. In the first phase, spend the early weeks rebuilding your fundamentals — go topic by topic through the core theory of your trade, diploma branch or B.Sc subject, making short notes of formulas, definitions and key concepts you can revise quickly later. In the second phase, shift to objective practice — solve subject MCQs in volume, always under the 0.33 negative-marking rule, so accuracy and judgement become second nature. In the final phase, move to full-length timed papers and revision of your weak areas, simulating exam conditions so the real test feels familiar. This structure works because it builds knowledge first, then speed, then exam temperament, in the right order.
Two preparation mistakes cost candidates the most. The first is spending too long on the comfortable topics they already know and avoiding the hard ones — the exam does not skip your weak areas, so neither should you. The second is treating mock tests as a scoreboard for the ego rather than a diagnostic tool; a mock you analysed for an hour after solving teaches you far more than three mocks you solved and forgot. Build your plan around honestly fixing weaknesses, and your score will climb faster than it would from simply doing more questions.
General awareness and aptitude — the smaller share
While the technical subject dominates, some ISRO written tests include a portion of general aptitude or reasoning, so it is worth a light, steady touch rather than heavy investment. Basic quantitative aptitude, logical reasoning and, where applicable, general English or awareness can be kept warm with short, regular practice — fifteen minutes a day is usually enough to stay sharp without stealing time from your core technical revision. The key is proportion: do not let aptitude practice crowd out the subject preparation that actually carries the weight in this exam. Confirm from the official notification and previous papers whether your specific post includes an aptitude section and in what proportion, then allocate your time accordingly.
Trade-wise focus areas for technician posts
For Technician-B and Draughtsman-B candidates, the written test is rooted in your specific ITI trade, so it helps to know the broad focus areas your trade typically covers. An Electronics trade candidate should be strong on basic electronics, components, circuits, measurements and instruments; an Electrical trade candidate on electrical machines, wiring, safety, measurements and basic power concepts; a Fitter or Mechanic trade candidate on workshop practice, tools, measurements, fitting and maintenance fundamentals; and a Draughtsman on drawing standards, projections, dimensioning and the conventions of technical drawing. Whatever your trade, the questions stay close to the practical theory you learned during your ITI — the safety rules, the standard procedures, the measurements and the working principles you would actually apply on the job.
Because of this, your single best preparation resource is your own ITI coursebooks and trade theory notes, supplemented with a good trade-specific objective question bank. You are not being asked to learn anything new or exotic; you are being asked to demonstrate that you genuinely command the trade you are certified in. Revise the fundamentals until they are automatic, practise objective questions in your trade until your accuracy is high, and the technician written test becomes a fair test of knowledge you already have.
Why ISRO sets a subject-deep test — and what that means for you
It is worth understanding the logic behind ISRO's exam design, because it tells you how to prepare. ISRO is not hiring generalists who happen to have a certificate — it is hiring people who will operate, maintain and support sensitive technical and scientific systems, where genuine command of the discipline matters every single day. That is why the written test goes deep into your subject rather than spreading thin across general knowledge: the organisation needs to verify that you actually understand your trade or branch, not just that you can clear a competitive cut-off. For you, this is reassuring — there are no tricks or surprise sections to fear, only the expectation that you truly know your own field. Prepare with that mindset, and you are preparing exactly the way the exam rewards.
Final exam-day strategy
On the day of the written test, your strategy is as important as your knowledge. Read every question fully before answering — a misread question is a wasted mark and, with negative marking, a costly one. Make a first pass attempting only the questions you are confident about, then a second pass on the ones you can solve with a little thought, and leave the rest rather than gambling marks on blind guesses. Keep an eye on the clock so you never leave easy questions unattempted at the end. Above all, stay calm: you have prepared your subject, the test is set in exactly that subject, and a steady, accurate performance on the questions you know is what converts preparation into a place on the merit list.
