Our previous genetic map for chromosome 17 has been expanded to include 72 loci defined by 90 RFLP markers and four microsatellite markers assayed by the polymerase chain reaction. Forty-one of these loci were ordered with odds greater than 1000:1 against local inversion, and the other 31 were ordered within 95% confidence limits. From the set of 41 unambiguously mapped loci, 14 well-spaced "index markers" can be extracted for efficient genetic studies. The complete map spans 173 cM (136 cM in males and 214 cM in females); average spacing between markers is 4.2 cM.