Background and Objectives: To investigate the relationship between geriatric nutritional risk index (GNRI) and osteoporosis (OP) in postmenopausal elderly women with type 2 diabetes mellitus (T2DM). Methods and Study Design: A total of 141 postmenopausal elderly women with T2DM was divided into OP and normal bone mineral density (BMD) groups, the differences in GRNI levels between the two groups were compared. According to the tertile levels of GRNI, T2DM were divided into three groups (T1, T2, T3 groups), and the differences in OP prevalence and levels of BMD among the three groups were compared. Results: Among postmenopausal elderly women with T2DM, GNRI levels were lower in the OP group compared to the normal BMD group [(103±5.46) vs. (105±5.46), p<0.05)]. With elevated GNRI levels, the BMD levels of femoral, total hip, total body, and lumbar vertebrae (L) were gradually increased, which were higher in the T3 group than in the T1 group (all p< 0.05). GNRI levels were positively correlated with the BMD levels of femoral, spine, total hip, total body, L1, L2, L3, L4, and L1-L4. GNRI was an independent influencing factor for the occurrence of OP (OR=0.887, 95%CI [0.795,0.988]). The ROC curve showed that the GNRI combined with serum ALP and P levels had a high predictive value for OP, with an area under the curve of 0.725 (p<0.01). Conclusions: In postmenopausal elderly women with T2DM, GNRI was independently and positively correlated with BMD levels. GNRI may be a predictor development of OP.