OSSC CHSL Exam Pattern 2026: Prelims, Mains and Marking

The OSSC CHSL exam pattern for the 2025 recruitment is set out in Advertisement No. 728/OSSC dated 2 March 2026, issued by the Odisha Staff Selection Commission. Selection runs in three stages: a 150-mark preliminary exam common to all posts, a 200-mark main written exam with a technical paper for each post, and certificate verification.

This page explains each stage, the marking scheme and negative marking, the shortlisting ratios that decide who moves forward, and how the final merit list is drawn up. It also turns the numbers into a time plan, because in a negatively marked paper, how you use the 2 hours matters as much as what you know.

Table of Contents

OSSC CHSL Exam Pattern at a Glance

The Commission decides whether each stage runs on OMR sheets or as a Computer Based Recruitment Examination (CBRE). The 2025 prelims was held through CBRE on 25 September 2026 in three sittings.

OSSC CHSL Preliminary Exam Pattern

• One paper: All candidates write the same prelims paper, whichever posts they applied for.

• No fixed section split: OSSC does not fix section-wise marks, so the share of each topic can vary between cycles.

• Qualifying rule: OSSC may fix minimum qualifying marks by category and by post. At least five times the category-wise vacancies are called for the main exam.

• Prelims exemption: Candidates with +2 Vocational (Fisheries) who apply only for Junior Fisheries Technical Assistant may go directly to the main exam.

OSSC CHSL Main Written Exam Pattern

The advertisement fixes the technical paper at 200 marks but does not give the number of questions, the duration or the marks per question. These details are expected in the main exam notice, so check the OSSC website before you finalise a time plan. The topic lists are on the OSSC CHSL syllabus page.

• Language: Both the prelims and the main exam are conducted in Odia and English. You choose the medium in the online application, and the choice cannot be changed later.

• Shortlisting: Based on main exam marks, candidates numbering two times the vacancies, post-wise and category-wise, are called for certificate verification.

OSSC CHSL Marking Scheme and Negative Marking

• Marks per question: In the prelims, 150 questions carry 150 marks, so each question is worth 1 mark.

• Negative marking: 0.25 marks are deducted for each wrong answer in the prelims. The advertisement sets the general rule as one quarter of the question's marks when there are four options, and one third when there are three.

• Unanswered questions: No penalty is stated for questions left blank.

• Normalisation: If an exam runs in several batches with different question sets, OSSC applies the normalisation formula published in its Notice No. 2444/OSSC dated 2 September 2021.

• No re-evaluation: There is no re-checking or re-evaluation of scores.

What the Pattern Means for You

• A wrong guess costs a quarter mark: Four wrong answers wipe out one correct answer. A guess pays off only when you can rule out at least two options.

• Speed target: With 150 questions in 120 minutes, you get 48 seconds per question on average. Bank time on current events and computer questions so you can spend it on Data Interpretation sets.

• Prelims is a gate, mains is the decider: Prelims marks are not added to the final merit, apart from breaking ties. Clear the prelims with a safe margin and put serious hours into the 200-mark technical paper.

• Category-wise shortlisting: Because five times the vacancies are called category-wise, the qualifying score can differ sharply between categories and between posts with very different vacancy counts.

For example, if you attempt 120 questions with 100 correct and 20 wrong, your prelims score is 100 minus 5, or 95 out of 150. Attempting 10 more blind guesses at the usual one-in-four success rate would add about 2.5 marks and take away about 1.9, which is close to no gain for the time spent.

How the shortlisting ratios play out

The ratios in the advertisement give a rough idea of how many candidates move forward in each category. The figures below are minimums for the main exam call, because OSSC calls at least five times the vacancies, and it can call more.

A post with few vacancies in your category leaves little room, so if you apply for more than one post, list them in the order you genuinely prefer. OSSC allots posts on merit-cum-preference and will not change an allotted post later.

Certificate Verification

Shortlisted candidates bring original certificates, mark sheets, caste and special category certificates and other documents listed in Annexure B of the advertisement, with self-attested photocopies and a signed copy of the application. Candidates who do not attend certificate verification are not considered for selection.

OSSC CHSL Final Merit and Tie-breaking

The merit list is prepared category-wise, equal to the number of vacancies advertised, from marks secured in the main written exam, taking into account the post preferences you gave in the application. If two candidates have the same score, OSSC applies these rules in order until the tie is resolved:

1. Higher marks in the preliminary exam.

2. Date of birth, with the older candidate placed higher.

3. Alphabetical order of names.

For example, if two Junior Forensic Attendant candidates both score 150 out of 200 in the main exam, the one with the higher prelims score ranks above. So even though the prelims is a screening stage, every mark there still counts if a tie arises.

Admission Letter and Exam-day Rules

• Admission letter: OSSC does not post admission letters. Download them from the OSSC website for each stage and carry a printout to the venue.

• Identity proof: Carry an original photo ID such as Aadhaar, voter card, driving licence or PAN card, with proof of date of birth if the ID does not show it.

• Prohibited items: Mobile phones, whether switched on or off, Bluetooth devices and other electronic gadgets are treated as malpractice.

• OMR care: In an OMR exam, fill roll number and other details correctly with a blue or black ball point pen. Incorrect or incomplete entries can lead to zero marks.

• Complaints: Any complaint about how the exam was conducted must reach the Commission by email within five days of the exam.

Time Management and Exam-day Strategy

A suggested plan for the 2-hour prelims

• Practise in the real format: Timed full-length mocks of 150 questions in 2 hours show whether this split works for you.

• Track accuracy, not just attempts: Aim to keep accuracy above 85 percent in mocks before you push for more attempts.

• Reporting rules: The 2025 prelims had reporting times 90 minutes before each sitting and gates closing 30 minutes before the exam, so plan travel to the centre accordingly.

Older pages may still show a different pattern from earlier cycles or other OSSC exams, so follow the current advertisement and the notices on the official OSSC website.