2021 Dates

  • Open exam registration starts: September 14, 2020

  • Student registration ends: December 4, 2021

  • USABO & Art of Problem Solving (AoPS) Student Registration Closes: December 11, 2021

  • Open exam competition: February 11, 2020

The Competition

USABO is part of the major US high-school-level Olympiads. Other US Olympiads include USAMO (USA Math Olympiad), USAPhO (USA Physics Olympiad), USNCO (US National Chemistry Olympiad), and USACO (USA Computing Olympiad), and more


Each USAXO (this is the shorthand for all the major olympiads as they mainly differ in one letter depending on what subject they are) competition's job is to select Team USA to compete at the international olympiad counterpart. USABO is responsible for choosing Team USA for the IBO (International Bio Olympiad). Similarly, USNCO chooses Team USA for ICO (Chemistry) and USAPhO chooses Team USA for IPO (Physics).


Each USAXO has its own way of qualifying. For USABO there are three stages of testing before you can have the honor of being a Team USA member (a very very prestigious achievement that will practically guarantee you admission into top STEM schools like MIT and other Ivy League Schools).


Usually around over 10,000 students register for the Open Exam. The top 500 of the Open exam students move to the Semifinals stage. From there, 20 students are chosen to go to a 2-week-long intense training "summer camp" at the end of which they take a theoretical exam and a practical (meaning actual lab techniques etc) to compete for one of the four coveted spots on Team USA. The four chosen Team USA members will then fly internationally to compete in the IBO. Past international IBO host countries include Hungary, UK, Iran, Vietnam, etc.

Our club aims to not only prepare passionate students for this prestigious competition in a fun way, but to interest them in the field of biology for future careers or pathways as well.

For more information, visit:

IBO Practicals Testing Site
IBO Practicals Testing Site

2021 USABO Brochure
2021 USABO Brochure

USABO IBO Hall of Fame
USABO IBO Hall of Fame

IBO Practicals Testing Site
IBO Practicals Testing Site


Books to Study


Campbell and Reece's BIOLOGY (8th edition or higher preferred) is the official textbook for USABO, so make sure you read through this textbook!


Author: Reece

8th Edition ISBN-13: 978-0805368444

9th Edition ISBN-13: 978-0321558237

10th Edition ISBN-13: 9780321775658

11th Edition ISBN-13: 978-0134093413

If you are interested, these textbooks focus on a specific topic are helpful as well!
Human Physiology by Sherwood
Gives an in-depth explanation of each of our body's systems.
Essential Cell Biology by Alberts 
Explores cellular and molecular biology.
Plant Biology by Raven
The specifics of plant anatomy, physiology, structure, and function.

The Exams

Tier 1

Open Exam

  • 50 minutes

  • 50 MCQ with one response per question

  • No penalty for guessing

  • Top 10% advance to semis

Tier 2


  • 120 minutes

  • Part A: MCQ with one answer, Part B: MCQ with multiple answer, Part C: short answer or multiple T/F

  • No penalty for guessing

  • Top 50 receive an honor certificate

  • Top 20 advance to training camp and finals

Tier 3

Camp & Finals

  • All-expense paid 12-day trip to a top university

  • 10 days of instruction and 2 days of testing

  • 6-hour practical test (dissections, labs, hands-on data analysis)

  • 3-hour theoretical

  • Top 4 represent USA at IBO


Tier 4


  • All-expense paid 6-day trip to a country such as Japan, Hungary, and Brazil 

  • The opening ceremony, theoretical exam, practical exam, closing ceremony

  • Top 10% gold, next 20% silver, next 30% bronze