Polymorphisms in the oxytocin receptor gene, OXTR_rs53576, have been linked to differences in maternal sensitivity and depressive symptoms. Although some studies suggest the A allele confers risk for mood disorders, individuals homozygous for the G allele may exhibit greater sensitivity to both positive and negative social experiences, including in the mother-infant dyad. Given the bi-directional nature of mother-infant influences on maternal mood, we tested the association between both mothers' and infants' OXTR_rs53576 genotype and maternal depression, as assessed through a self-report inventory. Although Beck Depression Inventory (BDI-II) scores were significantly higher for GG in comparison to AG/AA mothers, and for mothers of GG in comparison to AG/AA infants, an ANCOVA revealed that after sociodemographic risk factors had been controlled, infants', but not mothers', OXTR genotype predicted maternal depression scores, with no significant interaction between the two. The effect of infant OXTR on maternal depression was not explained by maternal reports of difficult infant temperament. We propose that GG infants have an enhanced capacity for processing both positive and negative socially meaningful contextual information, first amplifying and then differentially perpetuating negative affectivity in mothers who exhibit depressive characteristics. K E Y W O R D Sinfant temperament, mood disorders, oxytocin receptor gene, postpartum depression | 497 ASHERIN Et Al.