OBJECTIVE To investigate the association of a calcium-sensing receptor (CaSR) gene missense polymorphism, 986Ala/Ser (A986S), with bone mineral density (BMD) and bone size in healthy Chinese premenopausal women. METHODS A total of 285 healthy Chinese premenopausal women (20.0 to 41.9 years of age) of Han nationality in the urban area of Shanghai were recruited for this study. The BMD and bone size of the spine and hip were measured by dual-energy X-ray absorptiometry. All the subjects were genotyped at the CaSR A986S site in exon 7 with polymerase chain reaction followed by restriction enzyme BsaHI digestion. The presence of the restriction fragment site was represented by alanine (A), while its absence by serine (S), rendering the genotypes AA, AS, and SS. RESULTS The genotype AS was rare and SS absent in these Chinese women, and no significant differences in the BMD or bone size of either the spine or hip were found between the two genotypes. CONCLUSIONS Given the important role of the CaSR in calcium metabolism, further studies with useful genetic markers may have better chances to define the association of the CaSR gene with bone phenotype variations.