Purpose: To determine the association of Mitral Valve prolapse and keratoconus.Patients and Methods: In this case-control study, 62 patients with definite keratoconus and 167, age and sex matched controls were selected. All participants underwent complete ophthalmic examination and corneal topography. In addition, a comprehensive cardiac exam including M-mode, two-dimensional, and doppler echocardiography was performed. Definite cases of MVP were determined according to Perloffs criteria. Comparisons were made using t-test, Chi-square test, Mantel Haenzel test, and Fishers exact test.Results: Overall, mean age (SD) was 29.8 (12.3) years and the two groups were similar regarding age and sex. In the keratoconus group, 14 patients (22.6%) and in the control group, 11 patients (6.6%) had definite MVP (P=0.009). The odds for having MVP was 4.2 for patients versus controls (95% confidence interval: 1.9-11.3). The odds ratio increased in the third decade and slightly decreased in the fourth decade.Conclusion: This study revealed an association between keratoconus and MVP, therefore it seems prudent to refer patients with keratoconus to cardiologists for work-up and consider bacterial endocarditis prophylaxis when appropriate.