Aim: Focal segmental glomerulosclerosis (FSGS) is one of the most common glomerulonephritis (GNP) worldwide. Despite treatment, it may progress to end-stage renal disease. In the present study, we compared clinical and histopathological data on FSGS with primary and secondary GNP retrospectively. Methods: We retrospectively analyzed data on clinical and laboratory findings, treatment response, and risk factors associated with mortality in patients, who had been diagnosed with FSGS and other GNP via renal biopsy between January 2009 and December 2014. The average follow-up time was 22 (8-76) months. Results: FSGS and primary GNP were more frequently seen in males than in females (55.9% vs. 65.3%, p=0.033). Nephrotic syndrome was more common in patients with FSGS (41.2%) and primary GNP (57.7%), while chronic renal disease was more frequent in patients with secondary GNP (35%). In FSGS, the complete remission rate was 54.4%. 63.2% of patients had continued to receive treatment. According to the biopsy findings, interstitial inflammation and fibrosis were observed in 100% and 98.5% of patients with FSGS, respectively (p=0.010 and p