Maternal cannibalism is a condition whereby a dam consumes her own offspring after killing them. Although biological factors such as low levels of serum oxytocin and lipid levels have been shown to link to failure in maternal behaviors in different animals, underlying mechanisms responsible for abnormal maternal behavior has not yet been investigated in detail in dogs. To fill this gap, this study aimed to investigate serum lipid and oxytocin levels of the dogs having a previous history of maternal cannibalism. Mature female Kangal dogs with a history of maternal cannibalism (n = 15) and with a normal postpartum history (n = 15) were enrolled in the study. Serum oxytocin and lipid levels were significantly lower in dogs with a previous history of maternal aggression (P < 0.05). Findings of this study suggest that oxytocin is an important neuroendocrine factor in dogs for the normal onset of maternal behavior. Furthermore, low levels of high-density lipoprotein, low-density lipoprotein, and cholesterol might be contributing factors for development of abnormal maternal behavior. Thus, low levels of oxytocin and lipids should be taken into consideration in dogs with abnormal maternal behavior.