Multiple sclerosis (MS) patients, with a second autoimmune disease after lymphocyte depletion, had elevated serum IL-21 before and after treatment which correlated to IL21 genotypes. In addition, the IL21 gene has been associated to several other autoimmune diseases. However, in a Spanish population there was no association to MS. Here, in a Swedish cohort (2090 MS cases and 1732 controls) 12 single nucleotide polymorphisms (SNPs) tagging IL21 were not associated to disease. There was no interaction with risk alleles of IL21R and HLA-DRB1*15. Lack of genetic association was confirmed in a meta-analysis with pooled data from the present study and the Spanish study. In conclusion, IL21 has not been shown to be a major risk gene for MS.