Anatomy instruction has evolved over the past two decades as many medical schools have undergone various types of curricular reform. To provide empirical evidence about whether or not curricular changes impact the acquisition and retention of anatomy knowledge, this study investigated the effect of variation in gross anatomy course hours, curricular approach (stand-alone versus integrated), and laboratory experience (dissection versus dissection and prosection) on USMLE Steps 1 and 2 Clinical Knowledge (CK) scores. Gross anatomy course directors at 54 United States schools provided information about their gross anatomy courses via an online survey (response rate of 42%). Survey responses were matched with USMLE scores for 6,411 examinees entering LCME-accredited schools in 2007 and taking Step 1 for the first time in 2009. Regression analyses were conducted to examine relationships between gross anatomy instructional characteristics and USMLE performance. Step 1 total scores, Step 1 gross anatomy sub-scores, and Step 2 CK scores were unrelated to instructional hours, controlling for MCAT scores. Examinees from schools with integrated curricula scored slightly lower on Steps 1 and 2 CK than those from stand-alone courses (effect sizes of 2.1 and 1.9 on score scales with SDs of 22 and 20, respectively). Examinees with dissection and prosection experience performed slightly better on Step 2 CK than examinees in courses with dissection only laboratories (effect size of 1.2). Results suggest variation in course hours is unrelated to performance on Steps 1 and 2 CK. Although differences were observed in relation to curricular approach and laboratory experience, effect sizes were small. (Contains 4 tables and 3 figures.)