Purpose: This study was designed to investigate the effects of information sharing between students on results of clinical performance examination (CPX). Methods: 143 third-year students, who completed their core clinical clerkship, were randomly assigned to one day of a 3-day, 6 station CPX. Station checklists, scored by the SPs, consisted of history taking, physical examination, information sharing, clinical courtesy and patient-physician interaction. We compared the CPX station scores, CPX domain scores, self assessment scores and GPA of the three groups tested on different days with ANOVA, and analyzed the differences in CPX scores, after controlling for GPA, with ANCOVA. The correlations among the CPX total and domain scores, self assessment and the GPA of the 3rd year students were calculated. Data regarding information sharing between students and self-assessment were obtained through student questionnaires. Results: CPX total scores, self assessment scores and GPA of 3rd year students from day-2 were significantly higher than scores from day-1 or day-3. Checklist analysis showed that PE, CC and PPI scores were significantly higher on day-2, but Hx and IS scores were not significantly different. Results from questionnaires showed that 43% of students shared evaluation information. And CPX total scores had little correlation with self assessment scores. GPA of 3rd year students showed a similar pattern with the CPX totalscore. Conclusion: There is information sharing occurring between students during clinical performance examinations. Although there are significant differences in CPXscores for the treatment group, it seemed that CPX scores are not affected by information sharing between students. Reliability of information sharing from other students is low. The generalization of this study should be interpreted carefully.