This study evaluated the presence and importance of tricuspid regurgitation (TR) late after mitral valve replacement (MVR), as assessed both clinically and echocardiographically. The study showed that late TR was identified by echocardiography in 67% of patients, and was clinically relevant in more than one-third of cases. Age and female sex were identified as statistically significant predictors for late clinical TR development, though only age was found as a statistically significant predictor for echocardiographic TR development. In contrast, pre- and postoperative pulmonary artery pressure, predominant mitral lesion, prosthetic valve gradient and regurgitation were similar in patients with and without late TR. According to the high prevalence of late TR found, we conclude that a lower threshold for tricuspid valve repair should be considered when mitral valve surgery is performed.