OBJECTIVES Following mitral valve repair for Barlow's disease, recurrent mitral regurgitation (MR) is believed to occur frequently and is mainly attributed to disease progression. METHODS Between January 2000 and December 2015, 180 patients (40% women, mean age 58.7 ± 13.5 years) with Barlow's disease underwent mitral valve repair. To provide a longitudinal assessment of mitral valve repair durability, a multistate model for interval-censored observations (4 states: 1, Grade 0/1+ MR; 2, Grade 2+ MR; 3, Grade 3+/4+ MR; 4, reintervention/death) was developed. The mechanism of recurrent MR was assessed echocardiographically. RESULTS Early mortality was 1.7%. After hospital discharge, 6 late reinterventions were performed. With death as a competing risk, the 10-year overall reintervention-free survival and reintervention rates were 79.8% (95% confidence interval 72.7-87.6%) and 4.5% (95% confidence interval 2.0-10.2%), respectively. Echocardiographic follow-up was available for 165 (93%) of hospital survivors with a total of 480 examinations. The incidence of both recurrent Grade 2+ and Grade 3+/4+ MR was relatively low up to 10 years after surgery. Grade 2+ MR did not always progress to higher regurgitation grade during the follow-up period. Grade 3+/4+ regurgitation was highly associated with valve-related morbidity and mortality. Recurrent MR (≥Grade 2+) was predominantly related to the technical aspects of valve repair. CONCLUSIONS Despite the complex valve abnormalities observed in patients with Barlow's disease, mitral valve repair can be performed with good early and late outcomes and low rates of recurrence of MR up to 10 years after surgery. Early and late valve repair durability is good and remains stable over time, suggesting that underlying disease progression has limited clinical significance.