Linkage analyses have identified four major MS susceptibility loci in Finns. Here we have fine mapped the region on chromosome 5p in 28 Finnish MS families. Marker D5S416 provided the highest pairwise LOD score, and multipoint and haplotype analyses restrict the critical region to about 5.3 Mb on 5p15 between markers D5S1987 and D5S416. Ascertaining for HLA type and geographical origin indicated that families with and without the HLA DR15 risk haplotype, as well as families within and outside an internal high-risk region, contributed to the linkage to 5p, implying the general significance for this locus in Finnish MS families.