There have been suggestions in the literature that IgA nephropathy may be familial. Genetic factors may influence the development of disease in an association between HLA antigens and IgA nephropathy. At the present time, no conclusion can be drawn. Here, two siblings with typical IgA nephropathy in three families are presented. A relation between HLA and IgA nephropathy was not detected in these family studies. The first family involved a 14-year-old girl and her brother, who at the age of 12 years were admitted to the hospital with macroscopic hematuria. All of the investigations, including serum IgA levels (104 mg/dl and 102 mg/dl respectively) showed normal kidneys with IgA deposition in the mesangium of the glomeruli. In the second family, a 15-year-old boy and his brother at nine years of age were admitted with macroscopic hematuria and gross hematuria, respectively. Laboratory investigations were normal. The serum IgA level (287 mg/dl) was normal in the first patient but the second was elevated at 485 mg/dl. IgA deposits were observed in the glomerular mesangium in these patients. The third family consisted of a 15-year-old boy and his nine-year-old sister who were both admitted with microscopic hematuria. Serum IgA levels (193 and 131 mg/dl, respectively) and laboratory investigations were normal. Renal biopsy specimens revealed C3 and IgA depositions in the glomerular mesangium of both siblings. In the first family the patients were HLA identical, while in the others the siblings were one-haplotype identical. Although IgA nephropathy and HLA antigens are strongly associated in the literature, we could not find this association.