Combined Defence Services (CDS) is a national level entrance exam conducted by Union Public Service Commission (UPSC) for recruiting candidates under Indian Military Academy (IMA), Indian Naval Academy (INA), Air Force Academy (AFA) and Officers Training Academy. 

The examination is conducted twice a year, and the duration of training is three years.

Though the candidate may give his preference for a particular wing of the Armed Forces, the final selection depends on his performance and place in the merit list.

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UPSC CDS EXAM DETAILS: Introduction, Eligibility Criteria, Selection Procedure and Preparation Tips


What is UPSC CDS Examination?

The Union Service Public Service Commission (UPSC) conducts Combined Defence Services Examination for shortlisting candidates for various positions in the Indian Defence Sector. UPSC CDS is conducted twice every year and selected candidates are admitted to various defence departments, like

1. Indian Military Academy

2. Officers Training Academy

3. Indian Naval Academy

4. Indian Air Force Academy

Visit OnlineTyari Blog to read more about UPSC CDS Examination:  UPSC CDS Combined Defence Services Career Prospects


What is the Eligibility Criteria for UPSC CDS Examination?

Nationality: A candidate must be either

(a) A citizen of India, or
(b) A subject of Nepal, or
(c) A subject of Bhutan, or
(d) A Tibetan refugee who came over to India before 1st January 1962 with the intention of permanently settling in India, or
(e) A person of Indian origin who has migrated from Pakistan, Burma, Srilanka or East African countries of Kenya, Uganda, the United Republic of Tanzania, Zambia, Malawi, Zaire and Ethiopia or from Vietnam with the intention of permanently settling in India.

Note: Provided that a candidate belonging to categories (b), (c), (d) and (e), shall be a person in whose favour a certificate of eligibility has been issued by the Government of India. 

Age Limit for UPSC CDS Examination:

(1) For Indian Military Academy (IMA): Unmarried male candidates born not earlier than 02-01-1993 and not later than 01-01-1998.
(2) For Indian Naval Academy (INA): Unmarried male candidates born not earlier than 02-01-1993 and not later than 01-01-1998.
(3) For Air Force Academy (AFA): Unmarried male candidates age between 20-24 years as on 01-01-2017 (born not earlier than 02-01-1993 and not later than 01-01-1998).
(4) For Officers’ Training Academy: Male candidates (married or unmarried) born not earlier than 02-01-1992 and not later than 01-01-1998.
(5) For Officers Training Academy: Unmarried Women, issueless widows who have not remarried and issueless divorcees (in possession of divorce documents) who have not remarried are eligible. They should have been born not earlier than 02-01-1992 and not later than 01-01-1998. 

Note: Male divorcee/widower candidates can not be treated as unmarried male for the purpose of their admission in IMA/INA/AFA courses and accordingly they are not eligible for these courses.

Educational Qualification for UPSC CDS Examination:

(a) For I.M.A. and Officers’ Training Academy: Degree from a recognized University or equivalent.

(b) For Indian Naval Academy: Degree in Engineering from a recognized university/institution.

(c) For Air Force Academy: Degree of a recognized University (with Physics and Mathematics at 10+2 level) or Bachelor of Engineering.

Note: Those candidates who are studying in the final years Degree course and have yet to pass the final year Degree examination are also eligible to apply.

UPSC CDS: Selection Procedure Details:

UPSC CDS Selection Procedure consists of three stages:

1. Written Examination

2. Interview 

3. Document Verification/ Medical Examination. 

Interview/ Personality Test: The candidates who are selected in written test are called for interview. The SSB procedure consists of two stage selection process-Stage I and Stage II. Only those candidates who clear the stage I are permitted to appear for Stage II.
Stage 1 for SSB Interview: Stage I comprises of Officers Intelligence Rating (OIR) tests are Picture Perception Description Test (P&DT). The candidates will be shortlisted based on the combination of performance in QIR Test and PP and DT.
Stage 2 for SSB Interview: Stage II comprises of Interview, Group Testing Officers Tasks, Psychology Tests and the conference. These tests are conducted over 4 days.

The personality of a candidate is assessed by three different assessors viz. the interviewing Officer (IO), Group Testing Officer (GTO) and the Psychologist. There are no separate weightages for each test. The marks are allotted by assessors only after taking into consideration the performance of the candidate holistically in all the test.


1. As the course is large, everyday 2-3 hours study is necessary on a regular basis. Course may be divided into small chapters & proper study plan will bring sure success.

2. Previous years question papers can be used to know the exam pattern & the important topics to shorten the course.

3. For the Social Science (History, Geography, etc) part, NCERT Books of class 6th, 7th and 8th are good enough; class 9th & 10th NCERT books will cover all the aspects with additional information to those of class 6th, 7th & 8th.

4. English can fetch you really good marks. So to prepare English along with other subjects is required. Thorough understanding of PARTS OF SPEECH will help you do well in error finding.

5. There is negative marking, avoid giving wrong responses, only tick the option when you are sure about them. In other words, avoid guesses, it will help you.

6. Keep wrist watch with yourself to keep pace with the time, avoid stress, keep calm. In the last five minutes of the exam, tick all your responses in one go in the OMR Sheet. Be conscious, leaving the space  empty if you have not solved that question.

UPSC CDS Examination is conducted in three parts (Elementary Mathematics, General Knowledge, and English) of 120 minutes each. However, for Officers Training Academy OTA, there are only two papers, General Knowledge and English having 120 minutes each.   

(A) For Admission to Indian Military Academy, Indian Naval Academy, and Air Force Academy:

Subject Duration Maximum Marks
English 120 minutes 100
General Knowledge 120 minutes 100
Elementary Mathematics 120 minutes 100

(B) For Admission to Officers’ Training Academy:

Subject Duration Maximum Marks
English 120 minutes 100
General Knowledge 120 minutes 100


The maximum marks allotted to the written examination and to the interviews will be equal for each course. i.e the maximum marks allotted to the written examination and to the interviews will be 300, 300, 300 and 200 each for admission to the Indian Military Academy, Indian Naval Academy, Air Force Academy and Officers Training Academy respectively.

The papers in all the subjects will consist of objective type questions only. The question papers of General Knowledge and Elementary Mathematics will be set bilingually in Hindi as well as English.

UPSC CDS Syllabus Details:

The question paper will be designed to test the candidates’ understanding of English and workmanlike use of words.

General Knowledge including knowledge of current events and of such matters of everyday observation and experience in their scientific aspects as may be expected of an educated person who has not made a special study of any scientific subject. The Paper will also include questions on History of India and Geography of nature which Candidate should be able to answer without special study.

Arithmetic: Number System-Natural numbers, Integers, Rational and Real numbers. Fundamental Operations addition, subtraction, multiplication, division, Square roots, Decimal, fractions. Unitary method, time and distance, time and work, percentages, applications to simple and compound interest, profit and loss, ratio and proportion, variation.
Elementary Number Theory- Division algorithm. Prime and composite numbers. Tests of divisibility by 2, 3,4,5,9 and 11. Multiples and factors. Factorisation Theorem. H.C.F. and L.C.M. Euclidean algorithm, Logarithms to base 10, laws of logarithms, use of logarithmic tables.

Basic Operations, simple factors, Remainder Theorem, H.C.F., L.C.M. Theory of polynomials, Solutions of quadratic equations, the relation between its roots and coefficients (Only real roots to be considered). Simultaneous linear equations in two unknowns-analytical and graphical solutions. Simultaneous linear inequations in two variables and their solutions. Practical problems leading to two simultaneous linear equations or inequations in two Variables or quadratic equations in one variable & their solutions. Set language and set notation, rational expressions and conditional identities, Laws of indices.

Sine x, cosine x, Tangent x when 0 <x < 90 Values of sin x, cos x and tan x, for x = 0, 30, 45, 60 and 90
Simple trigonometric identities.
Use of trigonometric tables.
Simple cases of heights and distances.

Lines and angles, Plane and plane figures, Theorems on (i) Properties of angles at a Point(ii) Parallel lines, (iii) Sides and angles of a triangle, (iv) Congruency of triangles, (v) Similar triangles, (vi) Concurrence of medians and altitudes, (vii) Properties of angles, sides and diagonals of a parallelogram, rectangle and square (viii) Circles and its properties including tangents and normal, (ix) Loci.

Areas of squares, rectangles, parallelograms, triangle and circle. Areas of figures which Can be split up into these figures (Field Book), Surface area and volume of cuboids, lateral surface and volume of right circular cones and cylinders, surface area and Volume of spheres.

Collection and tabulation of statistical data, Graphical representation, frequency Polygons, histograms, bar charts, pie charts etc. Measures of central tendency.

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