Focal segmental glomerulosclerosis (FSGS) is a clinicopathologic syndrome with a substantial risk for progression to end-stage renal disease (ESRD). Recent studies of renal biopsy archives in the United States suggest that the incidence of FSGS has increased. FSGS has become the leading cause of idiopathic nephrotic syndrome in the United States, with the greatest incidence rates in the black population. In the absence of a population-based estimate of FSGS incidence, we wished to obtain a population-based estimate of incident ESRD cases caused by FSGS (FSGS ESRD) and characterize temporal changes in this group.