Transporters associated with antigen processing and presentation (TAP1 and TAP2) have been considered candidate genes in MS susceptibility based on evidence from experimental animal models confirming antigenic peptide selection by transporter polymorphisms and by the proximity of these transporter genes to the DR- and DQ-associated alleles known to confer disease risk in man. We report here an association study examining the influence of TAP gene polymorphisms on MS susceptibility in a Canadian patient population. Our results do not support a role for the five polymorphisms examined in the etiology of this disease.