Resting state functional connectivity networks (rs-FCNs) reflect the degree of functional-metabolic coherence of anatomically interconnected brain regions, with the degree of subregional connectivity within rs-FCN predicting individual differences in cognitive and emotional function. Anterior cingulate cortex (ACC), an integrative center for cognitive-behavioral and emotional-autonomic, motor neural networks with structural and functional heterogeneity, is one of the core elements of OCD pathophysiologic loop - cortical - basal ganglia – thalamic – cortical loop. The aim of this study was to investigate rs-FCNs of ACC subdivisions in obsessive-compulsive disorder (OCD). 21 OCD patients recruited from the OCD clinic at Seoul National University Hospital and 22 healthy volunteers (NC) underwent a resting-state functional magnetic resonance imaging (fMRI) scan. After resting state functional connectivity maps were depicted using 10 ROIs systematically placed throughout caudal, rostral, and subgenual ACC as seed regions, statistical analyses were done for within-group and between-groups. Rs-FCNs showed rostral/caudal and dorsal/ventral functional distinction in both groups. Even though the brain regions having significant functional connectivity with the seed regions of ACC subregions were overlapped between the groups of OCD and NC, between-group analyses revealed significantly weaker functional connectivity of OCD group in the claustrum, thalamus, medial frontal gyrus, inferior parietal lobule and posterior cingulate gyrus. The only brain region showing stronger functional connectivity in the OCD group was superior frontal gyrus. OCD patients were shown to have significantly weaker functional connectivity to the ACC subregions, which could be a reflection of inefficient cognitive and emotional control in OCD symptomatology.