In a series of 6,521 consecutive autopsies of infants and children, renal cysts were found in 136 cases (2%). Of these, 71 were females and 65 males; 103 patients had died in their first month of life. The different types of cystic disease represented were as follows: renal cystic dysplasia 65, cortical cysts in syndromes of multiple malformations 42, polycystic disease 16, simple cortical cysts 7, renal cysts in hereditary syndromes 3, and renal medullary cystic disorders 3. Extrarenal malformations were encountered in 102 of the 136 cases with renal cysts. Gastrointestinal malformations and in particular esophageal atresia very often appeared to be associated with renal disease. Esophageal atresia was found in 29 (21 %) cases, 20 in cases with renal cystic dysplasia and 9 in cases with cortical cysts in syndromes of multiple malformations. The possibility of renal cystic disease should therefore be kept in mind in infants with congenital malformation(s), especially those with esophageal atresia.