Matrix metalloproteinase-9 (MMP-9) is suggested to play a role in MS by mediating T cell migration across subendothelial basement membrane and by contribution to myelin breakdown. We studied the association of MMP-9 -1562 C/T gene polymorphisms with MS susceptibility and severity in 187 patients from Serbia. The significant decrease in T allele carriership (p = 0.01), was found in female MS patients. In addition, a trend toward lower MSSS in T allele carriers was noticed (CC, mean 5.7 +/- 2.5 vs. CT+TT, mean 4.9 +/- 2.5). Further studies in different populations are needed to resolve the potential influence of MMP-9 gene polymorphism on MS.