Schimke immuno-osseous dysplasia (SIOD) is a rare hereditary disease characterized by skeletal dysplasia, immune deficiency and progressive renal disease. Kidney involvement mainly determines the prognosis. The most common renal pathology is focal segmental glomerulosclerosis (FSGS). Medullary nephrocalcinosis refers to the diffuse deposition of calcium salts in renal medulla and has not previously been identified in SIOD. Here we report the first case of a pediatric patient having typical features of SIOD with medullary nephrocalcinosis.