Objectives Medullary cystic kidney disease (MCKD) is a tubulointerstitial nephropathy leading to end-stage renal failure. We combine the clinical and pathological characteristics as well as laboratory examinations to discuss the diagnosis of MCKD. Methods A total of 156 individuals with tubulorinterstitial nephropathy were assigned into 3 groups, acute tubulointerstitial nephropathy (ATIN), chronic tubulointerstitial nephropathy (CTIN) and MCKD. Clinical data and pathological findings were analyzed. Immunohistochemistry staining of uromodulin was performed for MCKD cases. Urinary uromodulin concentrations in MCKD and 99 healthy people were tested by ELISA. Results The age at diagnosis was much younger in MCKD than in CTIN. Serum uric acid level was significantly higher in MCKD than in CTIN patients (P=0.011). Uromodulin staining by immunohistochemistry showed block mass and dense stain in tubular cells, while it was diffused in cytoplasm with apical reinforce in normal controls. Urinary uromodulin concentration was much lower in MCKD (P=0.047). Conclusions MCKD as one cause of tubulointerstitial nephropathy should not be ignored. Clinical data, pathological and laboratory examinations are useful for its diagnosis.