Recently the "DRD3" gene has been associated with ASD in two independent samples. Follow up analysis of the risk allele of the SNP rs167771 in 91 subjects revealed a significant association with a specific type of repetitive behavior: the factor "insistence on sameness" (IS) derived from the Autism Diagnostic Interview. This risk allele was associated with a decreased risk for IS, but not with any other symptomatology. Further study and replication of this finding is necessary, bearing in mind that these results would not be statistically significant if corrected for multiple testing. (Contains 2 tables and 1 figure.)