The neuropeptide oxytocin (OXT) plays an important role in complex socio-affective behaviours such as affiliation, attachment, stress and anxiety. Previous studies have focused on the amygdala as an important target of OXT's effects. However, the effects of OXT on connectivity of the amygdala with cortical regions such as medial frontal cortex, an important mediator of social cognition and emotion regulation, remain unexplored. In a randomized, double-blind, cross-over design, 15 volunteers received intranasal OXT or placebo prior to resting-state functional magnetic resonance imaging. OXT significantly increased connectivity between both amygdalae and rostral medial frontal cortex (rmFC), while having only negligible effects on coupling with other brain regions. These results demonstrate that OXT is a robust and highly selective enhancer of amygdala connectivity with rmFC, a region critical to social cognition and emotion regulation, and add to our understanding of the neural mechanisms by which OXT modulates complex social and cognitive behaviours.