Idiopathic focal segmental glomerulosclerosis (FSGS) is a common cause of glomerular disease. Although previous case reports suggesting a familial form of the disease exist in the literature, its significance has not been emphasized. We report on our experience with nine cases in four families, as well as a review of the literature, and provide evidence that a familial form of FSGS might represent a distinct genotypic and phenotypic subset of idiopathic FSGS.