The AP Biology Examination is three hours in length and is designed to measure a student's knowledge and understanding of modern biology.

The examination consists of a 90-minute, 120-item multiple-choice section, which examines the student's understanding of representative content and concepts drawn from across the entire course, and a 90-minute free-response section, consisting of four mandatory questions that encompasses broader topics.

In the free-response portion of the examination, usually one essay question is taken from Molecules and Cells, and another question focuses on Heredity and Evolution. Two questions generally focus on Organisms and Populations. Any of these four questions may require the student to analyze and interpret data or information drawn from laboratory experience, as well as from lecture material, and may require students to integrate material from different areas of the course.

The multiple-choice section counts for 60 percent of the student's examination grade, and the free-response for 40 percent. Within the free-response section, each of the four questions is weighted equally. The answers to the free-response questions must be in essay form; outlines alone or unlabeled and unexplained diagrams alone are not acceptable. The candidates should read each question carefully, organize their material neatly, and compose answers that are as comprehensive and precise as time permits.