The objective of this study was to evaluate the attitudes and beliefs of primary care physicians (PCPs) and obstetricians/gynecologists (O&Gs) in relation to the prevention and treatment of osteoporosis (OP) in postmenopausal women. A survey was mailed to a random sample of PCPs and to all O&Gs registered in the province of Alberta (Canada). The survey evaluated their practice patterns using closed-ended questions, Likert scaled items, and two case studies. Cases 1 and 2 were 52-year-old and 62-year-old healthy postmenopausal women, respectively, with no known risks for OP. Neither had received hormone replacement therapy (HRT). One hundred fifty-seven PCPs and 57 O&Gs participated in the study. Thirty-eight percent of the PCPs and 32% of the O&Gs stated that they never requested bone mineral density measurements (BMDm) in early postmenopausal women. Most would request BMDm only in the presence of risk factors. The most important criteria to request BMDm were chronic glucocorticoid use and recent fractures. For case 1, 7% of the PCPs and 11% of the O&Gs would request BMDm; 76% of the PCPs and 80% of the O&Gs would recommend HRT. For case 2, 29% of the PCPs and 47% of the O&Gs would request BMDm (p = 0.01); 43% of the PCPs and 49% of the O&Gs would prescribe HRT. In general, O&Gs were more inclined to intervene in relation to BMDm and HRT. O&Gs were also more likely to be influenced by clinical trials than PCPs (p < 0.001). Our findings show variations in the patterns of practice of physicians in relation to the prevention of OP. In general, use of densitometry appears to be low. The results of the case studies suggest that individual physician perceptions may be more influential than patient characteristics when requesting BMDm and prescribing HRT, particularly in older postmenopausal women. This group of healthy older women have approximately equal odds of being offered versus not being offered BMDm and HRT according to the physician they consult.