About the USA Biology Olympiad
The USABO is the premier biology competition in the United States, run by the Center for Excellence in Education, and the pathway to the International Biology Olympiad.
The premier biology competition of the USA
The USA Biology Olympiad (USABO) is run by the Center for Excellence in Education (CEE), a nonprofit dedicated to nurturing the next generation of scientific leaders. Each year the program reaches roughly 10,000 students, making it the most widely taken biology competition in the United States.
The USABO is built on the conviction that great biology education should reward genuine understanding — not rote recall. Its exams probe how students think across the full breadth of the life sciences: from the molecular machinery of the cell to the dynamics of entire ecosystems.
For students in China, the equivalent Open Exam (BIOUS) uses the same questions and judging standard as the US competition, giving every participant a true world benchmark.
Explore the China region →
Four stages to the world stage
The USABO runs in four progressive stages, from a single school-based exam to representing the United States at the International Biology Olympiad.
Open Exam
50 multiple-choice questions in 50 minutes, taken in school. Open to all Grades 9–12 students. This is also the China-region exam (BIOUS).
Semifinal Exam
The top 10% of Open Exam scorers who are US citizens or legal residents advance — approximately 600 students — to a longer, more demanding paper.
National Finals
The top 20 Semifinal scorers gather at a host university for a 12-day residential program combining instruction with rigorous lab and theory testing.
International Biology Olympiad
A four-student national team is selected to represent the USA at the IBO each summer.
The International Biology Olympiad
Each year the USABO culminates in the International Biology Olympiad, where a four-student team represents the United States against the best young biologists from countries around the world. Reaching the IBO is one of the highest academic honours available to a high-school student in the life sciences.
The 37th IBO will be held at Vilnius University, Vilnius, Lithuania, from 12–19 July 2026. The USA will send its four National Finals top scorers to compete in theory and practical laboratory rounds.
See the competition pathway →Seven areas of biology, tested in depth
The USABO syllabus covers the full breadth of biology. Questions are designed to reward understanding and application — not surface-level memorisation.
Cell Biology & Molecular Biology
Cellular structure and function, biochemical pathways, gene expression and molecular mechanisms.
Genetics & Evolution
Inheritance patterns, population genetics, mechanisms of evolution and speciation.
Plant Anatomy & Physiology
Plant structure, transport systems, photosynthesis, growth, reproduction and responses.
Animal Anatomy & Physiology
Organ systems, homeostasis, neural and endocrine signalling, and comparative anatomy.
Animal Behaviour (Ethology)
Innate and learned behaviours, communication, social organisation and behavioural ecology.
Ecology
Population and community dynamics, energy flow, nutrient cycles and ecosystem interactions.
Biosystematics
Taxonomic principles, phylogenetics, classification of the major kingdoms and their defining characters.
Taking the USABO from China
The China region (BIOUS) is run independently by ASDAN using USABO’s own papers and judging standard, so students in China sit exactly the same exam as their peers in the United States and earn nationally recognised awards by percentile.
For full details on registration, exam dates, award tiers and past results in China, visit the dedicated China-region page.
Explore the China region →Questions about the USABO?
Our advisors can help you understand the competition, the China-region pathway, and how to prepare.