The purpose of this retrospective cohort study was to report the clinical course of children and adolescents with primary focal segmental glomerulosclerosis (FSGS). The records of 110 patients with biopsy-proven FSGS admitted between 1972 and 2004 were retrospectively reviewed. Demographic, clinical and laboratory data were recorded and histopathological data were reanalyzed by one pathologist who had no information about the outcome of the patients. Renal survival analysis was performed using the Kaplan-Meier method. Differences between subgroups (response to corticosteroids) were assessed by the two-sided log rank test. The median age at admission was 5 years (range: 1-15 years). Forty-two patients (38.2%) presented with hematuria at admission, and 55 (50%) presented blood pressure levels above the 95th percentile. Mean follow-up time was 10 years (SD 5.5). Twenty-four patients (21.8%) presented chronic kidney disease (CKD). It was estimated that the probability of CKD was 8% at 5 years, 17% at 10 years, and 32% at 15 years after diagnosis of nephrotic syndrome. In conclusion, on the basis of the clinical and histological characteristics observed, apparently our cohort of idiopathic FSGS is comparable with other published series. However, the long-term overall renal survival seems to be better in our cohort.