We report a case of tubulointerstitial nephritis and uveitis (TINU syndrome) in a 16-yearold male adolescent. He had weakness, anorexia, weight loss and malaise. He had no ocular symptom at presentation. Impairment of renal function, tubular proteinuria, anemia, increased erythrocyte sedimentation rate, eosinophilia and hypergammaglobulinemia were detected. He had HLA-DR4, HLA-A3 and HLA-B51 positivity. HLA-B27 was negative. The renal biopsy showed interstitial cell infiltrates and tubular atrophy without granulomas in interstitium. Glomeruli showed mild mesangial hypercellularity. Immunofluorescent staining was uniformly negative. After administration of systemic corticosteroids, renal, ocular and constitutional manifestations regressed. Bilateral knee arthritis developed 2 months after stopping the steroid treatment and in which ultrasonography showed a Baker’s cyst in right. Oral sulfasalazine was started and local corticosteroid was injected into the cyst. Symmetrical synovitis regressed without taking systemic steroid treatment. TINU syndrome should be considered in the differential diagnosis of patients presenting with non-specific constitutional, visual and renal manifestations. During the follow-up, synovitis may develop rarely. This is the first case report of TINU syndrome with symmetrical synovitis and Baker’s cyst.