The ISRO UDC (Upper Division Clerk) & Assistant Exam 2026 is a popular Group ‘C’ recruitment conducted by the Indian Space Research Organisation (ISRO). The exam tests candidates on general aptitude, reasoning, and administrative skills required for clerical and assistant roles.
This article provides a complete syllabus, exam pattern, marking scheme, and preparation strategy for 2026 aspirants.
ISRO UDC & Assistant Exam Pattern 2026
As per the official pattern, the written test is objective (MCQ-based) and divided into four sections.
Exam Pattern Overview
| Section | Subject | Questions | Marks |
|---|---|---|---|
| Part A | General English | 50 | 50 |
| Part B | Quantitative Aptitude | 50 | 50 |
| Part C | Reasoning Ability | 50 | 50 |
| Part D | General Knowledge | 50 | 50 |
| Total | — | 200 | 200 |
Key Highlights:
- Total Questions: 200
- Total Marks: 200
- Duration: 120 minutes
- Type: Objective (MCQs)
- Negative Marking: -0.25 marks per wrong answer
The exam is common for both Assistant and UDC posts, with similar syllabus and pattern.
ISRO UDC Syllabus 2026 (Subject-wise)
1. General English
This section evaluates language understanding and communication skills.
Important Topics:
- Reading Comprehension
- Error Detection
- Sentence Improvement
- Fill in the Blanks
- Synonyms & Antonyms
- Idioms & Phrases
- Active & Passive Voice
- Direct & Indirect Speech
Focus on grammar accuracy and vocabulary usage.
2. Quantitative Aptitude
Tests basic mathematical and numerical ability.
Important Topics:
- Number System
- Percentage, Profit & Loss
- Ratio & Proportion
- Average
- Time & Work
- Time, Speed & Distance
- Simple & Compound Interest
- Data Interpretation
- Mensuration (basic)
Questions are generally 10th-level mathematics.
3. Reasoning Ability (General Intelligence)
Measures logical thinking and problem-solving ability.
Important Topics:
- Coding-Decoding
- Analogy & Classification
- Series (Number/Alphabet)
- Blood Relations
- Direction Test
- Seating Arrangement
- Puzzles
- Syllogism
- Non-Verbal Reasoning (Mirror, Image, etc.)
Includes both verbal and non-verbal reasoning questions.
4. General Knowledge (GK & Current Affairs)
Tests awareness of surroundings and current events.
Important Topics:
- Current Affairs (National & International)
- Indian History, Geography, Polity
- Economy & Budget
- General Science
- Space & ISRO Missions
- Computer Awareness
Focus on recent events + static GK.
ISRO Assistant/UDC Selection Process 2026
The recruitment process typically includes:
- Written Test (CBT/Offline)
- Skill Test (Qualifying Nature)
Skill Test Details
- Typing Test (Computer-based)
- Word Processing (MS Word, formatting, etc.)
- Qualifying in nature (marks not added to final merit)
Marking Scheme
- Correct Answer: +1 mark
- Wrong Answer: –0.25 mark
- Unattempted: 0 marks
Accuracy is important due to negative marking.
Best Books for ISRO UDC 2026 Preparation
Here are top recommended books (SSC-level standard):
General English
- Objective General English – S.P. Bakshi
- Wren & Martin English Grammar
- Word Power Made Easy – Norman Lewis
Quantitative Aptitude
- Quantitative Aptitude – R.S. Aggarwal
- Fast Track Arithmetic – Rajesh Verma
- SSC Maths – Arihant
Reasoning Ability
- Verbal & Non-Verbal Reasoning – R.S. Aggarwal
- Analytical Reasoning – M.K. Pandey
General Knowledge
- Lucent General Knowledge
- Manorama Yearbook
- Monthly Current Affairs Magazine
Books + previous papers + mock tests are the best combination for success.
30-Day Study Plan for ISRO UDC 2026: Week-wise Strategy
Week 1: Basics Strong करें
- English Grammar (rules + practice)
- Maths: Percentage, Ratio, Average
- Reasoning: Coding, Analogy
- GK: Static GK (History + Polity)
Week 2: Concept + Practice
- Maths: Time & Work, SI/CI
- Reasoning: Puzzles, Seating Arrangement
- English: Reading Comprehension
- GK: Current Affairs (last 6 months)
Week 3: Advanced Practice
- Full syllabus revision
- Solve 2 previous papers daily
- Start mock tests
Week 4: Final Revision + Mock
- Daily full-length mock test
- Weak areas improvement
- Revise formulas + vocabulary
- Practice typing test
Daily Study Plan (6–8 Hours)
| Time | Subject |
|---|---|
| 2 hrs | Quantitative Aptitude |
| 2 hrs | Reasoning |
| 1.5 hrs | English |
| 1.5 hrs | GK/Current Affairs |
Final Preparation Tips
- Solve at least 10+ previous papers
- Focus on accuracy (negative marking -0.25)
- Practice mock tests regularly
- Improve typing speed (important for skill test)
Final Words
The ISRO UDC & Assistant Exam 2026 is a balanced exam covering English, Maths, Reasoning, and GK. With a structured preparation strategy and consistent practice, candidates can easily crack this exam.
The key to success is:
- Strong fundamentals
- Regular mock tests
- Time management
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