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Brazilian Biology Olympiad (OBB): Official Outline of the Path to IBO

Brazil sends four students to the International Biology Olympiad (IBO) through the Olimpíada Brasileira de Biologia (OBB), a national contest that the IBO lists as established in 2005 and run today from Instituto Butantan in São Paulo.1,3 A 2026 news report says more than 193,000 students registered in the latest edition.2 This page outlines how the path works according to the sources we could read. It is a map of the structure, not an insider’s account of what the exams feel like. We could not open the official website, and several facts come from Portuguese news reports, so those depend on our own translation.

Programme
Olimpíada Brasileira de Biologia (OBB), the IBO's own spelling1
Organiser
Instituto Butantan, São Paulo1,3
Who can enter
Enrolled high school students under 19, registered through their school1,3
Stages
School test, state-level test, final round at Butantan, IBO team of four
Official website
olimpiadasdebiologia.butantan.gov.br, as listed by the IBO; we could not open it
Language
Portuguese for the national contest; the IBO itself is in English

The path at a glance

Stage What happens How sure we are
Round 1 A multiple choice test taken at your own school, in the spring Good that it exists; the format varies between our sources
Round 2 A larger multiple choice test at selected schools in each state; about the best 5% advance Medium; this comes from the IBO page and may be out of date
Final round A week of written and practical exams at Instituto Butantan Medium; the 2026 news report and the IBO page differ on how many reach it
IBO team The top four of the final; places five to eight go to the Ibero-American olympiad Medium; stated by the IBO page and repeated in a 2026 news report

Stage 1: the school round

The IBO’s country page describes a first round of 30 multiple choice questions taken at the student’s own school, usually in late March, which only eliminates and gives no prize.1 A 2023 news report on the registration deadline gives phase dates of 10 March, 31 March and 27 April that year, which is a different schedule from the IBO page.3 The IBO page says about 100,000 students from over 2,100 schools took part in 2022.1 Dates change every year, so read the current notice on the official site.

Stage 2: the state-level round

The second round is, according to the IBO page, 100 multiple choice questions taken at selected schools in each state; about the best 5% advance, the top 16 go on to the final, and 150 medals are awarded at this stage.1 The 2023 news report describes a second phase of 50 questions instead.3 The differences are written up once in the box below.

Stage 3: the final round at Instituto Butantan

The IBO page describes the final as one week of written and practical exams at Instituto Butantan, with no prizes at this stage.1 A May 2026 news report on medallists from Pernambuco speaks of a final training stage at Butantan with theory and practical classes, to which the winners are invited.2 That report is in Portuguese and our reading of it is our own translation.

Stage 4: the IBO team

The IBO page says the top four of the final round represent Brazil at the IBO, and the next four go to the Ibero-American Biology Olympiad (OIAB).1 The 2026 news report says the same in its own words.2 The sources we could read give no further detail on the training before the IBO or on any extra selection step after the final round. A 2026 report from a Portuguese newspaper says Brazil took first place overall at the 2025 OIAB in Colombia and that Butantan hosts the 2026 OIAB in São Paulo.4

Points for an Author

If you went through this programme yourself, these are the points we most need you to settle. They are grouped here so that nothing uncertain is buried in the text above.

Where the sources disagree

  • The round structure. The IBO page gives a 30 question first round, a 100 question second round with the top 16 advancing, and a week-long final.1 The 2023 news report gives a 50 question second phase and a single written exam as the third phase on 27 April.3 This may be a change between editions or an out-of-date IBO page; we could not tell which.
  • How many reach the final stage. The IBO page says 16.1 The 2026 news report appears to describe about 20 students, which is our own calculation from the article and not a stated figure.2
  • Who organises it. The IBO lists Instituto Butantan.1 A 2013 news report names the Associação Nacional de Biossegurança with ministry and state agency support,5 and a 2026 Portuguese newspaper says Butantan has run the OBB since 2017.4 The IBO page still gives 2005 as the founding year.
  • How many students take part. The IBO page says about 100,000 in 2022 and 140,000 in 2020,1 and the 2026 report says more than 193,000.2 These are different years rather than a true conflict.

Gaps a firsthand author could fill

  • The official rules. The official website refused our requests, so we have not read a current regulation.
  • The exact dates, question counts and quotas for the current year, and how many students reach the final.
  • How the four IBO team members are decided: by final rank alone, or by extra tests.
  • The length and content of the training before the IBO.
  • Brazil’s IBO medal results for 2025 and 2026. We did not find a medal table for either year.
  • What the tests and the week at Butantan are actually like, and what students wish they had known.

A firsthand author can settle every one of these points. If that could be you, email us or read how it works.

BiOGuide tips for students aiming at this path

These are general tips from BiOGuide, not advice from a Brazilian participant, and they apply to any student aiming at an IBO team.

  • Train for the international format early. The IBO papers are in English and test reasoning on data and experiments, not only recall. The IBO preparation guide explains the format, and past IBO papers are in our practice papers.
  • Practise the practical side. The final round and the IBO both include practical exams, so learn the lab techniques. Our practical notes start at practical 1.
  • Cover the core areas. Our notes on cell and molecular biology, genetics, ecology and evolution are a sensible base.
  • Learn the English terms. Even if you study in Portuguese, learn the English names of structures, processes and methods, because the IBO papers are written in English.
  • Use the official channels for anything dated. Registration, dates and formats change every year. Your school and the current notice from the organiser decide, not us.

Official links and sources

  1. International Biology Olympiad, country page for the Olimpíada Brasileira de Biologia. ibo-info.org. The page is undated; it carries figures up to 2022. In English.
  2. Diario de Pernambuco, 11 May 2026, on Pernambuco students in the national biology competition (in Portuguese). diariodepernambuco.com.br
  3. Jornal Contábil, 9 March 2023, on the registration deadline (in Portuguese). jornalcontabil.com.br. It is three years old and describes one edition only.
  4. DN Brasil, 31 July 2026, on the Ibero-American Biology Olympiad hosted in Brazil (in Portuguese). dnbrasil.dn.pt
  5. Agência FAPESP, 26 July 2013, on Brazilian medals at the IBO (in Portuguese). agencia.fapesp.br. Old, used only for the organiser history.

One more note on sources. The IBO’s list of national olympiads includes Brazil as a member; it is undated. The official site named there, olimpiadasdebiologia.butantan.gov.br, returned an access refusal when we tried it, so nothing in this guide was read from it.

This outline was last checked on 8 October 2026 and will age. Spotted an error or out-of-date detail? Email r6394175@gmail.com.