Family medicine predoctoral programs frequently have medical students record patient diagnoses in logbooks. Little is known about the accuracy of such logbooks. No studies have compared patient records dictated by students with cases recorded in logbooks. Over 2 years, all patient encounters dictated by 79 medical students during their 8-week family medicine rotations were recorded and compared with information in the students' logbooks. Students dictated 2,520 patient encounters but only recorded 2,085 (82.7%) of them in their logbooks. Still, this rate of inclusion is higher than other studies where students did not dictate patient encounters. On the average, each student saw and dictated 32 patient encounters but omitted five to six from their logs. There were no significant differences between the 10 honors and 69 non-honors students in the proportion of patients omitted from logbooks. Medical students underreport patient encounters in clerkship logbooks. Keeping a record of the patients dictated by medical students was helpful in determining the accuracy of students' logbooks.