The cases are reported of two young children who developed insulin-dependent diabetes mellitus (IDDM) within 2 weeks of receiving a diagnosis of nephrotic syndrome. Neither patient responded to 8 weeks of daily prednisolone. The first patient presented at 2 years and 9 months of age. Her renal biopsy showed mesangial proliferation. The second child presented with steroid resistant nephrotic syndrome at 18 months of age and developed IDDM 2 weeks later. He achieved partial remission with cyclosporine therapy. His initial renal biopsy at 3 years of age showed minimal change disease and follow-up renal biopsy at 5 years of age showed early diabetic glomerulosclerosis. Tests for NPHS2 and WT1 genetic mutations were negative in both patients. To our knowledge this is the first report of steroid resistant nephrotic syndrome with almost simultaneous onset of IDDM in young children.