USMLE Step 3 has either 13 or 14 cases on the second day of the exam. Step 3 is a total of a two-day exam where the first day you have 12 blocks of 20 multiple choice questions and the second day you have 9 blocks of 20 multiple choice questions followed by 13–14 CCS cases.
Study for the CCS section of Step 3 at StudyCCS.com
March 2026 Format Update
Starting on March 10th, 2026, Step 3 changed to have shorter, more frequent blocks. Now on Day 1, you will have 12 blocks of 20 multiple choice questions. On Day 2, you will have nine more blocks of 20 question multiple choice question blocks, followed by 13 or 14 CCS cases.
Day 1: High-Yield Content
The highest yield content for Day 1 of USMLE Step 3 is biostatistics, ethics/communication, and medication mechanisms of action (with the highest yield being antibiotic mechanism). The majority of students use UWorld to prepare for the general content and supplement their studying with biostatistics and ethics/communication videos on YouTube. For antibiotic mechanisms, the majority of students use the Mechanism of Action (MOA) review with StudyCCS.com.
Day 2: Multiple Choice & CCS Cases
For Day 2, there are effectively zero biostatistics, ethics/communication questions. The most common type of questions on Day 2 of Step 3 are prognostic factors/risk factors for various conditions. These questions are most similar to questions you would see on Step 2. After the multiple choice question blocks, you will have 13 or 14 CCS cases.
In these cases, you will have a patient present either to the office or to the ED and your job is to work them up, transfer them, and manage their condition. The most common question for this section is: "How many practice CCS questions do I have to do to feel prepared on test day?" We answer this question here.
In short, it takes about 15 cases to master the interface. Then, your goal is to do as many cases as possible to build up your clinical knowledge. The best way to do a bunch of cases quickly is to use the SpeedOrder simulation.