IL7 is a nonredundant cytokine, essential for T cell survival and development in humans. We genotyped nine tagging single nucleotide polymorphisms (SNP), representing all parts of the IL7 gene, in 1,210 Swedish multiple sclerosis (MS) patients and 1,234 healthy controls. None of the SNPs showed a significantly different distribution in MS, and haplotype analysis also failed to reveal differences between patients and controls. We conclude that the IL7 gene is very unlikely to influence the genetic susceptibility to MS in this population.