Objective: In this study we investigate the quantitative diffusion tensor imaging (DTI) changes of normal-appearing white matter (NAWM) in patients with stage 0 asymptomatic HIV-1 associated dementia complex (HAD), and clinical factors contributing to it. Materials and methods: Conventional magnetic resonance imaging (cMRI) and DTI were performed in 40 patients with stage 0 asymptomatic HAD (24 patients with CD4 þ counts <200 cells/mm 3 , 16 patients with CD4 þ counts >200 cells/mm 3 ) and 40 healthy volunteers with similar gender/age. Quantitative DTI values-fractional anisotropy (FA)/apparent diffusion coefficient (ADC) of normal-appearing white matter (NAWM) in frontal, parietal, temporal, occipital lobes, genu, splenium and body of the corpus callosum (CC), corona radiate (CR), centrum semiovale (CSO), and anterior and posterior limbs of the internal capsule were measured and analyzed. Results: The mean FA values were much lower and the mean ADC values were significantly higher in the CC body and CSO in stage 0 HAD patients than in the controls (P < 0.05). In comparison with controls, the patients with stage 0 asymptomatic HAD had significantly higher ADC values (P < 0.05) for frontal, parietal, occipital lobes, CC body, CR and CSO, FA values of the corresponding regions were reduced, but the differences were not statistically significant (all P > 0.05). FA values were reduced and ADC values were higher in other white matter regions, but did not show any significant difference between the two groups (P > 0.05). Significantly higher ADC values in the frontal and CR in patients with CD4 þ counts <200 cells/mm 3 compared with the patients with CD4 þ counts >200 cells/mm 3 and the controls. Conclusions: Quantitative DTI could help better evaluation of white matter abnormalities in stage 0 asymptomatic HAD, this may be helpful for early and accurate prevention and treatment of HAD, and for preventing or reversing cognitive decline. The quantitative DTI value changes indicated that in early phase of HAD there is a preferential occult injury of frontal lobe and CSO. Nadir CD4 þ count may be a great risk for HAD.