Compulsive individuals are habitually indecisive, and indecision reaches its pathological apex in obsessive-compulsive disorder (OCD). With the increasing interest in the neurobiology of decision-making, it may be useful to conceptualize OCD as a disorder of decision-making. A selective review of the neurobiological studies of the decision-making process was performed, and the convergence with the understanding of the neurobiology of OCD examined. The dorsolateral, orbitofrontal and anterior cingulate cortices are engaged in multiregion neural subsystems that interact with each other to retain information online, manipulate options, make choices and maintain goals. These interact with the limbic regions, especially the amygdala, in relation to history of reward and emotional valence relating to a choice, and the basal ganglia for behavioural execution. Abnormalities in these regions also characterize OCD and related disorders, therefore leading to problems in making some decisions that are affect-laden by nature or association. Conceptualizing OCD as a disorder of decision-making leads to new approaches for its investigation, and novel strategies for both physical and behavioural-cognitive treatments.