In this study, it was aimed to investigate apoptosis in renal injury and the effect of lisinopril in rat model, which constitute unilateral ureteral obstruction. The retroperitoneal ureter was ligated with a 4.0 silk for the experimental model of ureteral obstruction in Wistar albino rats. Untreated group (n = 20) received no treatment. For the lisinopril-treated group (n = 20), 20 mg/kg/day of drug was given orally. Ultrastructural differences were analyzed using electron microscopic technique; apoptotic distribution was analyzed using the TUNEL method. After electron microscopic evaluation, on the 4th and 14th day in the untreated group, edema in the glomeruli, loss of microvillus and apoptotic cells in proximal tubule cells and sclerosis in the glomeruli were detected. On the 4th day in the lisinopril-treated group, the kidney was ultrastructurally normal and a less number of apoptotic cells were only observed on the 14th day. On light microscopic examination on the 4th and 14th day in the untreated group, while the glomeruli were normal in structure, the boundary of the proximal tubule was disrupted and some picnotic cells in both the proximal and collecting tubules were observed. In both 4th and 14th day of the lisinopril-treated group, kidney showed normal structure, although in some places picnotic cells in the collecting tubules were observed. In conclusion, lisinopril was effective and it may prevent early renal damage in the direct obstruction model.