Autosomal recessive polycystic kidney disease (ARPKD) is one of the major hereditary nephropathies in children predominantly presenting in early childhood. The clinical picture is variable but there is a fatal outcome in many cases. We have performed linkage analysis in 16 ARPKD families and localized the ARPKD gene to chromosomal region 6p21-cen with no evidence for genetic heterogeneity among different clinical phenotypes. Linkage was confirmed using six adjacent microsatellite markers and the highest lod score of 7.42 was obtained with D6S272 at theta = 0.00. Our findings should lead to more accurate forms of prenatal diagnosis than those currently available using ultrasound.