We have constructed a high-resolution genetic linkage map spanning the proximal 32 cM of mouse chromosome 17 including the t complex. Simple sequence repeats at D17Tu1 and D17Mit6 were employed to identify 121 recombinants among 374 offspring of a (C57BL/6 x CAST/Ei) x C57BL/6 backcross. In contrast to previously reported interspecific Mus domesticus x Mus spretus backcrosses, we did not observe inversion polymorphisms with our cross. This and the relatively high frequency of DNA polymorphisms between C57BL/6 and CAST/Ei allowed us to put 32 RFLV markers and 32 PCR markers on a single map. We present the localization of four new DNA markers and determined map positions for 10 other loci, which previously had been assigned to intervals of the t complex only through the study of partial t haplotype chromosomes.