Abstract Background: The aim of this study was to evaluate the QoL of patients undergoing heart valve replacement using the SF-36 questionnaire, compare it between patients with mechanical prosthesis and patients with bioprosthesis, and correlate the results with sociodemographic variables. Objective: To assess the QoL of patients undergoing heart valve replacement and compare it between patients with bioprosthetic valves and patients with mechanical prosthetic valves. Methods: We included 36 consecutive patients (16 men) with a mean age of 51 years and six months, who underwent mitral or aortic valve replacement from September 2007 to December 2011. The study was conducted between March and May 2012 and involved the application of the SF-36 survey and a sociodemographic questionnaire. Statistical tests were performed, and data are expressed as absolute frequency and percentile, and median and interquartile range (P25 and P75) (Mann-Whitney test), considering a significance of 95%. Results: The average time of surgery was 32.5 months (8-61 months). Participants were asked about the practice of physical activity, and 41.7% were physically active. For the SF-36 domains, the highest scores were observed for the social domain whereas the lowest scores were found for mental health, with a mean of 89.25 and 54.44, respectively. In the statistical analysis, we found statistically higher values in emotional functional for patients with mechanical valve prosthesis (p = 0.0084). Conclusion: The QoL of the patients undergoing heart valve replacement improves considerably after the surgery, except for the mental health domain, probably due to the low practice of physical activity. The type of prosthesis seems not to influence the QoL or the patients in the late postoperative period.