OBJECTIVE Adequate documentation of the outcome of treatment of pigmented villonodular synovitis (PVNS) is sparse. Available case series show relatively short follow-up times and often combine locations or subtypes to increase patient numbers. This article describes the long-term follow-up of a single institution's large consecutive series of PVNS. METHODS Retrospectively, 107 PVNS patients were identified between 1985 and 2011 by searching pathology and radiology records. Treatment complications, recurrences and quality of life were evaluated. Most patients (85.2%) were primarily or secondarily treated at our institution. RESULTS Both subtypes, localized PVNS [29 (27%)] and diffuse PVNS [75 (70%)] were represented. The knee was affected in 88% of patients. Treatments received were surgery, external beam radiotherapy, radiosynovectomy, targeted therapy, immunotherapy or combinations of these. Forty-nine (46%) patients had prior treatment elsewhere. The mean follow-up from diagnosis until last contact was 7.0 years (range 0.3-27.4) for localized PVNS and 14.5 years (range 1.1-48.7) for diffuse PVNS. The 1- and 5-year recurrence-free survival rates for diffuse PVNS were 69% and 32%, respectively. Quality of life, estimated by 36-item Short Form Health Survey (SF-36) scores, were not significantly different between localized and diffuse PVNS. However, both patient groups scored lower than the general population norms on the general health component (59.2 and 56.3, respectively, P < 0.05). CONCLUSIONS Recurrence rates of PVNS increase with time. Long-term follow-up shows, particularly in diffuse PVNS, it is a continually recurring problem, and over time it becomes increasingly difficult to cure. The quality of life is decreased in patients with PVNS compared with the general population.