BACKGROUND: Data is lacking about long-term impact of JJ stents (JJst) on renal parenchyma. The aim of the study was to assess the evolution of renal parenchyma in patients with JJst indwelling for more than two years, and to find predictive factors for the development of renal atrophy. METHODS: Consecutive patients with JJst indwelled for more than 24 months, with a history of cancer, were retrospectively included. Replacements of JJst were scheduled every six months, or earlier in case of premature obstruction. Patient characteristics at the time of insertion of JJst, history of indwelling JJst and most recent data (serum creatinine, cancer status, definite JJst removal, renal volume (RV) with3D software) were recorded. RESULTS: With a median follow-up of 4 years, 73 patients were included. The indication of JJst insertion was mostly external compression (65.8%). CT scans were available to assess RV evolution in 66 patients (90.4%). Median shrinkage of RV was higher when JJ stenting was unilateral versus bilateral: -40% (-63; -15) versus -16% (-36; -3), P<0.001. The duration of indwelling JJst was the only statistically significative predictive factor of renal shrinkage in multivariate analysis (OR [CI 95%]: 1.35 [1.10-1.66] P=0.004). Median relative change from baseline in eGFR was -22% (-45%; -5%.). No statistically significant predictive factors of eGFR evolution were found in univariate and multivariate analysis. CONCLUSIONS: Unilateral JJst for more than 2 years was associated with a significant shrinkage of renal parenchyma, especially since the duration of the indwelling stent was long.