Biology & Medicine · High school · US

USA Biology Olympiad

USABO, run by the Center for Excellence in Education, is the most substantial official biology competition in the U.S. and the sole pathway to the International Biology Olympiad. For applicants to biology, neuroscience, biochemistry, environmental science or BS/MD and pre-med tracks, it is among the clearest academic signals available: advancing from the Open Exam to the Semifinal (roughly the top 10%) already says something, while reaching the national top 50 or becoming a National Finalist places a student in the elite tier — persuasive across UC campuses, the Ivies and top liberal arts colleges. Participation is strong around Irvine and most schools are already registered; the real pitfall for local families is simply that entry must go through the school and close in November.

USA Biology Olympiad
2026-27Latest season

Photo: Yaroslav Shuraev / Pexels

  1. Registration opensAug 72026
  2. Registration deadlineNov 222026
  3. Contest datesFeb 3 – Mar 22027
  4. ResultsMar 302027

Verified from the official site on September 20, 2026 · usabo-trc.org

Organizer
Center for Excellence in Education (CEE)
Eligibility
Any student in grades 9-12 may sit the Open Exam. Students cannot self-register: a school (or a USABO-authorised test centre) must first register and pay, then enrol its students. Registering schools must be non-profit, led by a state-certified teacher or someone with a life-sciences degree, charge students no service fee, and have no commercial conflict of interest. Progression to the Semifinal and beyond requires U.S. citizenship or lawful permanent residency. Seniors formally enrolled in an undergraduate program are ineligible. Homeschooled students may take part by arranging with USABO before registration closes, sitting the exam at a local high school, and possibly covering the $125 fee themselves.
Format
Four stages, with the first two online. Open Exam: a 50-minute online multiple-choice test taken nationwide at one time, open to all registered students; roughly the top 10% advance. Semifinal Exam: a 120-minute online paper in three parts — Part A multiple choice, Part B multiple true/false, Part C short answer and/or essay tied to the current IBO themes — restricted to U.S. citizens and green-card holders. The top 50 qualify for the National Finals, and after a mandatory Zoom interview and pretest, 20 are confirmed as National Finalists. National Finals: an in-person program of about 12 days at a host university (10 days of instruction plus 2 days of testing) covering eight areas including cell biology, genetics and ecology, with a practical examination of roughly 6 hours and a theoretical examination of roughly 4 hours; the 2027 Finals are in person only. The strongest finalists form the U.S. team for the International Biology Olympiad.
Contest dates
February 3, 2027 · March 2, 2027
Fees
The school registration fee is a single flat $125 per school and covers all of that school's participating students; for the 2026-27 season payment is due by 23:59 Eastern Time on October 23, 2026. Registered schools are expressly barred from charging students an additional service fee. Homeschooled students may need to cover the $125 themselves.
Awards
The Open Exam awards Honorable Mention (top 20%) and Certificate of Merit (top 30%). The Semifinal recognises three tiers: Recognition of Academic Excellence (top 50), Honorable Mention (next 75) and Certificate of Merit (next 100). The top 50 qualify for the National Finals; after interview and pretest, 20 become National Finalists attending the university training and assessment program, with the best going on to represent the U.S. at the International Biology Olympiad, held in Warsaw, Poland in 2027.

About the competition

USABO, administered by the Center for Excellence in Education, is the premier high school biology competition in the United States and the official selection route to the International Biology Olympiad. It runs in four stages: Open Exam, Semifinal Exam, National Finals, IBO.

The Open Exam is a 50-minute online multiple-choice test taken simultaneously nationwide by all registered grade 9-12 students, spanning cell and molecular biology, genetics and evolution, plant and animal anatomy and physiology, ecology, animal behaviour and systematics — far beyond a standard school syllabus. Because the clock is tight, speed and judgment matter as much as breadth.

Roughly the top 10% advance to the Semifinal, where difficulty jumps sharply: 120 minutes across three parts, adding multiple true/false items that punish imprecise concepts and short-answer or essay questions tied to the current IBO themes. From this round, only U.S. citizens and permanent residents may compete.

The top 50 qualify for the National Finals; after a Zoom interview and pretest, 20 National Finalists attend a roughly 12-day residential program at a host university — 10 days of university-level instruction and lab training, then a practical examination of about 6 hours and a theoretical examination of about 4 hours.

For 2026-27: registration opens 7 August 2026, school payment closes 23 October, registration closes 22 November, the Open Exam is 3 February 2027, the Semifinal 2 March, finalists announced 30 March, National Finals 20-30 June, and the IBO in Warsaw 18-25 July 2027.

How to prepare

  • Work from a university general biology text such as Campbell, moving module by module through cell and molecular, genetics and evolution, plants, animal physiology, ecology and behaviour — AP Biology depth is not enough.
  • The Open Exam gives only 50 minutes, so drill timed full sets at about 40 seconds per question and practise eliminating fast when unsure; this round rewards accuracy and rhythm, not deep problem-solving.
  • Train specifically for the Semifinal's multiple true/false items: treat each statement independently and check the boundaries of the concept, especially absolutes like all, always and only — this is the main divider between qualifying and reaching the national top 50.
  • Track the current IBO themes and syllabus, since Semifinal Part C is built around them, and push your school to complete registration well before the 23 October payment deadline so paperwork never costs you the entry.

Frequently Asked Questions

Can an Irvine middle schooler take the USABO?

No. The USABO Open Exam is limited to students in grades 9-12, so eighth graders and younger cannot register. Ninth graders can and should sit it early: many eventual National Finalists take the Open Exam once in 9th or 10th grade simply to learn the question style, then push further each year. Note also that a graduating senior who has formally enrolled in an undergraduate program is no longer eligible.

How do I register for the USABO if my school isn't signed up?

Students cannot self-register for the USABO. A school or a USABO-authorised test centre must register first, pay a flat $125 per school, and then enrol its students. The fee covers every student at that school, and registered schools are not allowed to charge students an extra service fee, so the practical step is to ask the biology teacher to start the process early. Homeschooled students arrange directly with USABO before the deadline and sit the exam at a local high school.

For Irvine students, is the USABO Open Exam proctored at school or taken at home?

It is online but not at-home. The USABO Open Exam must be taken in person at the registered school or authorised test centre, proctored by a teacher, inside the window set by the Center for Excellence in Education — 3 February 2027 at 4pm ET for the 2027 season. The 120-minute Semifinal is proctored the same way. This applies to every Irvine public and private high school alike, so the teacher's involvement is unavoidable.

What's the difference between the USABO Open Exam and the Semifinal?

The Open Exam is a 50-minute multiple-choice paper with no penalty for guessing, broad in coverage but closer to solid high-school level, and open to every registered student. The Semifinal is a 120-minute exam in three parts: Part A multiple choice, Part B multiple true/false, and Part C short answer and essay tied to the current IBO practical topics. Only the top 10% of Open Exam scorers who are US citizens or permanent residents advance to it.

What USABO Open Exam score do Irvine public high schoolers need to make Semifinals?

There is no fixed cutoff. USABO advances roughly the top 10% of Open Exam scorers, and the threshold moves each year with paper difficulty; CEE publishes the season's cutoff table afterwards. On the recent 50-point papers the semifinalist line has landed in the twenties. Even without advancing, the top 20% receive an Honorable Mention certificate and the top 30% a Certificate of Merit, both of which can be listed on a college application.

Can international students without a green card do the USABO?

They can sit the Open Exam and earn its certificates, but the Semifinal, the National Finals and US team selection are restricted to US citizens and lawful permanent residents. A student here on an F-1 visa can therefore compete in round one and report the result on applications, but cannot advance further. Students in that position often pair the USABO Open Exam with an olympiad that has no citizenship restriction, such as the British Biology Olympiad.

How much of Campbell Biology do you need for the USABO?

For the Open Exam, Campbell's Biology on its own is essentially enough. Focus on cell and molecular biology, genetics, animal and plant physiology, ecology and evolution, and spend your time on a full read-through plus past papers rather than on obscure chapters. For the Semifinal and National Finals, Campbell is only the starting point: strong candidates add a specialist text such as Molecular Biology of the Cell and study the current IBO practical topics.

Is AP Biology at an Irvine public high school enough to do well on the USABO?

AP Biology is the floor, not the finish line. The USABO Open Exam covers more ground than AP and asks for finer detail, and students who scored a 5 on AP Bio often still fall short of the semifinalist cutoff on their first attempt. A realistic sequence is to take AP Biology in 10th grade, read Campbell and work through past USABO papers over the summer, then target the Open Exam and Semifinal seriously in 11th grade.

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