AIMS: The oxytocin receptor (OXTR) is implicated in the pathophysiology of autism spectrum disorder (ASD). A recent study found a rare non-synonymous OXTR gene variation, rs35062132 (R376G), associated with ASD in a Japanese population. In order to investigate the association between rare non-synonymous OXTR variations and ASD, we resequenced OXTR and performed association analysis with ASD in a Japanese population. METHODS: We resequenced the OXTR coding region in 213 ASD patients. Rare non-synonymous OXTR variations detected by resequencing were genotyped in 213 patients and 667 controls. RESULTS: We detected three rare non-synonymous variations: rs35062132 (R376G/C), rs151257822 (G334D), and g.8809426G>T (R150S). However, there was no significant association between these rare non-synonymous variations and ASD. CONCLUSIONS: Our present study does not support the contribution of rare non-synonymous OXTR variations to ASD susceptibility in the Japanese population.