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USA Biolympiad

USA Biolympiad (USABO)

An open biology exam that narrows to twenty finalists and the four-person United States team at the International Biology Olympiad.

Run by Center for Excellence in Education

Official website How to prepare Reviews and tips

Key facts

Eligible grades
Grades 9 to 12. AP courses are not required for success in the exams.
Source, checked 2026-09-02
Recommended preparation
Familiarity with a full first-year high school biology curriculum
Why: The exam series follows the International Biology Olympiad syllabus, spanning molecular and cell biology, genetics, anatomy and physiology, ecology and evolution. This is Compete's reading of the published content, not a stated entry requirement: the Open Exam is open to any eligible student and no coursework prerequisite is published.
Based on the official syllabus and content covered.
This is Compete's reading of the competition's documented content, not a requirement stated by the organiser. You may enter without it.
Compete guidance, not an eligibility restriction. Students outside this are still eligible if the official eligibility above allows them.
Eligible ages
For International Biology Olympiad eligibility: be 15 years old as of 1 January 2027 and not turn 19 before 31 July 2027.
The age rule governs progression to the international team, not entry to the Open Exam.
Source, checked 2026-09-02
Individual or team
Individual
Where it runs
Online · United States
Entry cost
A flat $125 registration fee per school, covering all participating students from that school, due by 23 October 2026.Per school, not per student, so the cost per student falls sharply the more a school enters.
Registration deadline
Two deadlines, both binding. The school must register and pay the $125 fee by 23 OCTOBER 2026. The final deadline for both schools and students to complete online registration is 15 NOVEMBER 2026. Student registration opened 7 August 2026. 44 days leftMissing the October school deadline blocks every student at that school, regardless of the November date.
Competition dates
The Open Exam is normally administered in late January or early February. The full 2027 calendar is published on the USABO site.
Difficulty
Highly competitiveNational-level field. Expect months of structured work, and usually a coach or a strong team.
Prizes
Recognition rather than cash: Open Exam Honorable Mention Certificate for the top 20% and Certificate of Merit for the top 30%, Semifinal Recognition of Academic Excellence, then Finals medals and international team selection.No cash prizes. Open Exam recognition includes an Honorable Mention Certificate for the top 20 percent and a Certificate of Merit for the top 30 percent. Twenty finalists attend the National Finals at Harvard University, and four are selected for the International Biology Olympiad team.

What USA Biolympiad is

USABO is the United States selection process for the International Biology Olympiad. It starts with an Open Exam that any registered high school student can sit at their own school, narrows to a Semifinal Exam for high scorers, then to twenty National Finalists who attend a residential training camp, from which four are chosen to represent the United States internationally. The content goes well beyond a school biology course, particularly in molecular biology, genetics and physiology.

How the competition works

A four-tier series. The Open Exam is a 50-minute online nationwide multiple-choice exam with one response per question and NO penalty for guessing, proctored in person at a registered school or authorised test centre. The Semifinal Exam uses multiple choice, multiple true/false and short answer. Both are administered ONCE only, on the Synap platform, on the published date and time. Test Administrators must complete an online Test Administrator Certificate including the revised 2026 USABO Honor Code.

Eligibility notes

The Open Exam is available to high school students registered through a school or authorised USABO Test Center. The Semifinal Exam is restricted to grades 9 to 12 students who are US citizens or legal permanent residents.

How to register

  1. Ask a biology teacher to register your school as a USABO testing centre before the autumn deadline.
  2. Sit the Open Exam at your school during the winter window.
  3. If you score highly enough nationally, you will be invited to the Semifinal Exam.
  4. Top twenty scorers become National Finalists and are invited to the training camp.

Register on the official site

What skills you need

  • Molecular and cell biology
  • Genetics
  • Plant and animal physiology
  • Ecology and evolution
  • Data interpretation
  • Exam technique under time pressure

How to prepare

USABO tests well beyond an ordinary high school biology course, and the single most effective preparation is working through Campbell Biology carefully rather than doing more practice questions. Students who place typically know the molecular and physiology chapters at a level closer to a first-year university course.

What to study

Cell and molecular biology
The largest slice of the exam. Membrane transport, signalling, respiration, photosynthesis, the cell cycle, and molecular genetics in detail.
Genetics and evolution
Mendelian and population genetics, linkage, gene regulation, phylogenetics, and quantitative problems on allele frequencies.
Anatomy and physiology
Animal systems in depth, particularly nervous, endocrine, circulatory and renal, plus plant structure and transport.
Ecology and behaviour
Population dynamics, community interactions, biogeochemical cycles, and animal behaviour.
Data interpretation
Many questions present an unfamiliar experiment and ask what it shows. This is a skill, and it is practised rather than memorised.

Full preparation guide, including a week-by-week plan

Recommended resources

Past problems and materials

Only materials the organiser or an authorised archive publishes openly are listed here.

Frequently asked questions

Can I register for USABO myself?

No. A school or approved testing centre must register and administer the Open Exam. Ask a biology teacher to register the school before the autumn deadline.

Is high school biology enough preparation?

No. USABO content goes substantially beyond a standard high school course, particularly in molecular biology and physiology. Most students who advance have worked through a university-level text such as Campbell.

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