Objective A substantial proportion of patients with rheumatic heart disease (RHD) have tricuspid regurgitation (TR). This study aimed to identify the impact of functional TR on clinical outcomes and predictors of progression in a large population of patients with RHD.Methods A total of 645 patients with RHD were enrolled, mean age of 47±12 years, 85% female. Functional TR was graded as absent, mild, moderate or severe. TR progression was defined either as worsening of TR degree from baseline to the last follow-up echocardiogram or severe TR at baseline that required surgery or died. Incidence of TR progression was estimated accounting for competing risks.Results Functional TR was absent in 3.4%, mild in 83.7%, moderate in 8.5% and severe in 4.3%. Moderate and severe functional TR was associated with adverse outcome (HR 1.91 (95% CI 1.15 to 3.2) for moderate, and 2.30 (95% CI 1.28 to 4.13) for severe TR, after adjustment for other prognostic variables. Event-free survival rate at 3-year follow-up was 91%, 72% and 62% in patients with no or mild, moderate and severe TR, respectively. During mean follow-up of 4.1 years, TR progression occurred in 83 patients (13%) with an overall incidence of 3.7 events (95% CI 2.9 to 4.5) per 100 patient-years. In the Cox model, age (HR 1.71, 95% CI 1.34 to 2.17), New York Heart Association functional class III/IV (HR 2.57, 95% CI 1.54 to 4.30), right atrial area (HR 1.52, 95% CI 1.10 to 2.10) and right ventricular (RV) dysfunction (HR 2.02, 95% CI 1.07 to 3.84) were predictors of TR progression. By considering competing risk, the effect of RV dysfunction on TR progression risk was attenuated.Conclusions In patients with RHD, functional TR was frequent and associated with adverse outcomes. TR may progress over time, mainly related to right-sided cardiac chambers remodelling.