To investigate whether examination grades of the students at the Zagreb University School of Medicine changed during the 1991-1995 war in Croatia.The retrospective descriptive study included examination grades from 5 major courses in the first 5 years of the medical studies: Anatomy (first year), Physiology (second year), Pathology (third year), Internal Medicine (fourth year), and Surgery (fifth year). We compared the war-period (1991-1995) with two control periods: before (1989-1990) and after the war (1996-2000). The passing grades at the Zagreb University range from 2 to 5, with 2 as the lowest and 5 as the highest grade. There were a total of 17,682 examinations from the 5 courses in the studied periods.Grades were higher in the pre-war and post-war periods than in the war period (p<0.001 for both comparisons). Grades in the individual courses followed the general trend, except for the surgery course, where grades during the war were better than in the control periods, and the physiology course, where continual worsening, irrespective of the war, was observed.Medical students obtained significantly lower grades in 5 major courses during the war than before or after it. Thus, it is reasonable to assume that different factors, some related and some unrelated to war, could have adversely influenced students performance.