PURPOSE: The aim of this study was to assess the psychometric properties of the Chinese (Mandarin) version of the Medical Outcomes Study Social Support Survey (MOS-SSS-CM) among people living with HIV/AIDS (PLWHA) in Mainland China. METHODS: A cross-sectional study was conducted with a convenience sample of 200 Chinese PLWHA. They completed the MOS-SSS-CM along with the Chinese version of the Beck Depression Inventory Revised (BDI-II) scale, the Zung Self-Rating Anxiety Scale (SAS), the Perceived Stress Scale (PSS-10), and the World Health Organization Quality of Life Brief (WHOQOL-BREF) scale. RESULTS: Internal consistency (Cronbach's α) was 0.97 for the overall MOS-SSS-CM and 0.82-0.91 for the five subscales originally proposed. However, 11 of the 19 items demonstrated unsatisfactory item discriminant validity. An exploratory factor analysis yielded a two-factor solution with tangible and social-emotional dimensions, which demonstrated satisfactory reliability and better discrimination between different subscales than did the original five-factor model. The concurrent validity of the two-factor scale was further confirmed by its significant negative correlations with the BDI-II (r=-0.41, p<0.01); the SAS (r=-0.27, p<0.01); and the PSS-10 (r=-0.30, p<0.01), and significant positive correlation with the WHOQOL-BREF scale (r=0.61, p<0.01). CONCLUSION: We found a two-factor solution for the MOS-SSS-CM, which demonstrated good reliability and validity when applied to Chinese PLWHA. This was consistent with results from a study of Taiwanese caregivers. Further validation in other populations and disease states is warranted.