Oxytocin (OT) and arginine-vasopressin (AVP) are 2 peptides that are produced in 
the brain and released via the pituitary gland to the peripheral blood, where 
they have diverse physiological functions. In the last 2 decades it has become 
clear that these peptides also play a central role in the modulation of 
mammalian social behavior by their actions within the brain. Several lines of 
evidence suggest their involvement in autism spectrum disorder (ASD), which is 
known to be associated with impaired social cognition and behavior. Recent 
clinical trials using OT administration to autistic patients have reported 
promising results. Here, we aim to describe the main data that suggest a 
connection between these peptides and ASD. Following a short illustration of 
several major topics in ASD biology we will (a) briefly describe the 
oxytocinergic and vasopressinergic systems in the brain, (b) discuss a few 
compelling cases manifesting the involvement of OT and AVP in mammalian social 
behavior, (c) describe data supporting the role of these peptides in human 
social cognition and behavior, and (d) discuss the possibility of the 
involvement of OT and AVP in ASD etiology, as well as the prospect of using 
these peptides as a treatment for ASD patients.