The aim of our study was to conduct a case-control study in a Chinese postmenopausal population to evaluate the roles of the IGF-1 rs35767 and rs972936 polymorphisms on bone mineral density (BMD) levels and osteoporosis risk. A total of 272 consecutive postmenopausal women with a primary diagnosis of osteoporosis and 272 controls were enrolled in the study between 2012 and 2014. The polymerase chain reaction-restriction fragment length polymorphism method was used to genotype the rs35767 and rs972936 IGF-1 polymorphisms. By comparing the demographic characteristics between patients and controls, patients with osteoporosis were found to be more likely to have a habit of alcohol drinking (P = 0.023). Furthermore, the BMD levels of the L1-L4 vertebrae, femoral necks, total hips, and trochanters in patients with osteoporosis were significantly lower than those in controls. By conditional regression analysis, we found that the IGF-1 rs2288377 and rs972936 gene polymorphisms were not associated with the risk of osteoporosis (P < 0.05). However, the CT+TT genotype of rs35767 and the AG+GG genotype of rs972936 were significantly associated with lower BMD levels in the femoral neck. Overall, our study suggests that IGF-1 rs2288377 and rs972936 gene polymorphisms do not influence the risk osteoporosis.