OBJECTIVE: The objective of this study was to estimate patient compliance with oral and vaginal metronidazole treatment of bacterial vaginosis using personal digital assistants (PDAs) and paper diaries. GOAL: The goal of this study was to assess a novel compliance documentation approach. STUDY: After each dose of intravaginal or oral metronidazole, 71 subjects recorded the time on a paper diary and answered questions on a PDA. All PDA entries were unknowingly time-date-stamped. Subjects returned for 2- and 6-week posttreatment examinations. Compliance was calculated using a repeated-measures multivariate analysis of variance (ANOVA). RESULTS: Mean patient compliance rates within the oral metronidazole group were greater with the paper diary compared with the PDA (68.3% and 50.0%, respectively, P = 0.001). The observed rate of compliance agreement for PDA versus paper diary was 69.0% (kappa = 0.4). The majority of noncompliant subjects reported they were compliant with the PDA and paper diary. CONCLUSIONS: PDAs could more accurately document true compliance rates and could be reasonable instruments to assess compliance in intravaginal antimicrobial drug or contraceptive trials.