How does Mexico choose its IBO team?

High school students compete in state contests, the best six from each state go to the national contest, and the best national finishers then train and take further evaluations. Four students represent Mexico at the IBO. The sources we could read do not give the exact rule for choosing those four.

Who organises the Olimpiada Nacional de Biología?

The IBO lists the Academia Mexicana de Ciencias (AMC) as the main organiser of the national round, with state universities running the first round.

The IBO's page says students enrolled in any of the high school modalities. The AMC site also mentions an age rule that we could not read clearly, so check it with the organisers.

Is this guide written by a Mexican participant?

No. It is an outline of the official picture from published sources, with tips from BiOGuide. We are looking for a Mexican olympiad participant or coach to write a firsthand guide and replace this one.

Olimpiada Nacional de Biología (Mexico): Official Outline of the Path to IBO

Mexico sends four students to the International Biology Olympiad (IBO) through the Olimpiada Nacional de Biología (ONB), a contest the IBO lists as founded in 1991 and run at national level by the Academia Mexicana de Ciencias (AMC).¹ 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. Most sources are in Spanish, so the facts taken from them depend on our own translation, and the official AMC pages we could read look out of date.

Programme: Olimpiada Nacional de Biología (ONB), the IBO's own spelling¹
Organiser: Academia Mexicana de Ciencias (AMC) for the national round; state universities run the first round^1,2
Who can enter: Students enrolled in high school (bachillerato)^1,2
Stages: State contest, national contest, training and selection, IBO team of four
Official website: amc.mx/olimpiadanacionaldebiologia; the address listed by the IBO did not load
Language: Spanish for the national contest; the IBO itself is in English

The path at a glance

Stage	What happens	How sure we are
State contest	Written exam in each of the 31 states, with some states also running a regional preselection	Good for the structure; the format comes from the IBO page
National contest	The best six students from each state sit theory and practical exams in a host state	Good for the quota; the exam format is reported differently by two sources
Training and selection	The best national finishers train and take further evaluations	Good that it exists; the rules are not stated
IBO team	Four students	Good for the size, from a 2026 university report

Stage 1: the state contest

The IBO’s page says the first round is run mainly by state universities for high school students in all 31 states, that ten states hold a regional olympiad beforehand as a preselection, and that the exam has 60 multiple choice and 40 true or false questions, with a practical test in seven states.¹ The IBO page places it in the last week of October. The AMC’s own pages say each state is represented by its top six finishers and give no format.³ A 2026 report in the UNAM university newspaper describes one Mexico City student’s path, which began with a first exam through the AMC olympiad and a city-level olympiad on 1 March 2025.⁴

Stage 2: the national contest

Six students from each state, the winners of the first round, go to the national contest, which moves to a different host state each year.^1,3 The IBO page describes a theory exam of 40 multiple choice and 60 true or false questions plus four practical tests, held in the last week of November.¹ The AMC’s page says about 160 students take part and that awards are given in three blocks (gold, silver, bronze) without a ranking inside each block.³ The 2025 national contest was held in Oaxaca from 10 to 13 November, with a theory exam and four practicals.⁴

Stage 3: training and selection

The AMC describes a third stage, the training and selection of the delegations that represent Mexico at the IBO and at the Ibero-American Biology Olympiad (OIAB).² The IBO page says students are trained for ten days, in April and June.¹ The UNAM report describes about eight months of training for a Mexico City student and, after the national contest, further training, evaluations and eliminations before the team is set.⁴ A 2023 news report says funding was an obstacle that year, and that parents paid for tickets and registration for the team.⁵

Stage 4: the IBO team

The UNAM report says four students go to the IBO, the student and three others.⁴ A 2023 news report also says the team that year was four students.⁵ The sources we could read do not say how the four are picked from the national finishers, beyond the evaluations and eliminations above.

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 national exam format. The IBO page gives 40 multiple choice and 60 true or false questions plus four practicals.¹ A search summary of a different page, which we could not open ourselves, described a three hour theory exam of about 200 questions with 72 students advancing to a practical round. We treat that second description as unconfirmed.
Timing. The IBO page puts the national contest in the last week of November,¹ and the UNAM report puts the 2025 one on 10 to 13 November.⁴ The IBO page may be out of date.
The size of each state delegation. The IBO and AMC pages both say six students per state.^1,3 A search summary of a state call from Querétaro, which we could not open, said four. Different states or years may use different rules.
The age of the AMC pages. The AMC pages we could read show 2019 as their year, so they describe an earlier edition than the UNAM report.^2,3

Gaps a firsthand author could fill

A current call. The address the IBO lists for the AMC site returned a not found error, and we found no 2025 or 2026 call from the AMC.
The age limit. The AMC page mentions a limit tied to turning 19 around the exam date, but its wording was unclear to us, so confirm it with the organisers.
The exact rule for choosing the four IBO team members, the number of evaluations, and how long training lasts.
The language of the exams, which no source we could read states.
Mexico’s IBO medal results for 2022 to 2025. We did not retrieve them.
What the state and national contests and the training 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 Mexican 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 national contest includes practical tests, and so does the IBO. 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 Spanish, 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 and differ by state. Your state coordinator and the AMC decide, not us.

Official links and sources

International Biology Olympiad, country page for the Olimpiada Nacional de Biología. ibo-info.org. The page is undated and some figures may be old. In English.
Academia Mexicana de Ciencias, home page of the Olimpiada Nacional de Biología (in Spanish; footer year 2019). amc.mx
Academia Mexicana de Ciencias, page on the national olympiad (in Spanish; refers to the 2019 edition). amc.mx
Gaceta UNAM, on a CCH Sur student on the way to the IBO (in Spanish; its byline appeared to say June 2026 but the site also showed a conflicting date). gaceta.unam.mx
Excélsior, 16 June 2023, on the team and its funding (in Spanish). excelsior.com.mx

One more note on sources. The IBO’s list of national olympiads includes Mexico as a member; it is undated.

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