Objective: To assess whether changes in proteinuria are associated with the incidence of myocardial infarction (MI) in patients with hypertension. Methods: The Kailuan study was a prospective longitudinal cohort study on cardiovascular risk factors and events. Hazard ratios with 95% confidence intervals (CIs) were calculated using Cox regression models. Results: A total of 24 926 hypertensive patients (mean age: 55.2 +/- 10.9 years) without previous MI were included. After a mean follow-up of 6.8 years, 382 (1.5%) individuals developed MI. Participants with proteinuria at baseline had a 60% higher risk for developing MI as compared with participants without proteinuria at baseline (hazard ratio: 1.60, 95% CI: 1.12-2.29) after adjusting for dyslipidemia, diabetes mellitus and other cardiovascular risk factors. Compared with participants without proteinuria, individuals with incident proteinuria or persistent proteinuria during the follow-up had 54 and 141% higher risks for developing MI, respectively (hazard ratio: 1.54, 95% CI: 1.14-2.09 and hazard ratio: 2.41, 95% CI: 1.59-3.66; all P<0.05). Conclusion: Proteinuria is associated with an increased incidence of MI, but the association is likely to be underestimated if baseline measurements of proteinuria are used. Measures of changes in proteinuria, particular persistent proteinuria, are more likely to reflect the lifetime risk for MI.