Purpose: To investigate whether global spontaneous brain activity changes in type 2 diabetes mellitus (T2DM) patients and these changes vary according to the degree of microangiopathy. Materials and methods: T2DM patients with (M+, n = 26) and without (M-, n = 22) microangiopathy as well as 28 healthy nondiabetic subjects were enrolled in this study. All the subjects completed a resting state functional magnetic resonance imaging (rs-fMRI) examination and neuropsychological assessment. Regional homogeneity (ReHo) values, representing spontaneous brain activity, were calculated and compared between M+ and M- T2DM patients and nondiabetic controls. Results: In both M+ and M- T2DM patients, ReHo values were decreased in the occipital lobe, temporal lobe, postcentral gyrus, and cerebellum, while increased in the bilateral precuneus, superior/middle frontal gyrus, and insula. Compared with the M- group, NV patients showed decreased ReHo values in the left cuneus and superior occipital gyrus. The ReHo values in the lingual gyrus/calcarine cortex and MTG were related to clinical parameters in T2DM patients. Conclusion: The abnormalities of spontaneous brain activity revealed by ReHo values in both M+ and M- T2DM patients may provide insights into the neurological pathophysiology underlying diabetes-related cognitive impairments. M+ patients showed more decreased brain activity related to severely impaired function of visual processing and visual memory. (C) 2015 Elsevier Ireland Ltd. All rights reserved.