We report on linkage analysis and haplotype characterization in 12 Cuban families with autosomal dominant polycystic kidney disease (ADPK) using PKD1-linked markers. They included both standard restriction fragment length polymorphisms (26.6., BLu24, and pGGG1) as well as microsatellite polymorphisms (CW2, 16AC2.5, and SM6). All of the examined families were fully informative for genetic diagnosis and no evidence of unlinked families was found. Analysis of two recombination events places PKD1 distal to the marker BLu24 and reduces the size of the region likely to contain the disease gene by approximately 300 kb. The allele frequencies of each marker were similar in the ADPKD and normal populations.