We report on linkage analysis and haplotype characterization in 40 Italian families with spinal muscular atrophy (SMA). The investigated loci included D5S6, D5S112, D5S39, and D5S76. No evidence of unlinked families was found. Thirty-two (80%) of the examined families were fully informative for prenatal diagnosis and carrier detection. The frequencies of individual alleles did not differ between SMA and normal chromosomes.