Background: Identifying and managing osteoporosis among cancer survivors is an important issue, yet little is known about the bone health of cancer survivors in Korea. This study was designed to measure the prevalence of osteoporosis and to assess related factors among Korean cancer survivors. Materials and Methods: This study was designed as a cross-sectional analysis. Data were obtained from dual energy X-ray absorptiometry measurement of the lumbar vertebrae and femoral neck, and from standardized questionnaires among 556 cancer survivors and 17,623 non-cancer controls who participated in the Fourth and Fifth Korea National Health and Nutrition Examination Surveys (2008-2011). We calculated adjusted proportions of osteoporosis in non-cancer controls vs. cancer survivors, and we performed multivariate logistic regression analysis. Results: The prevalence of osteoporosis among cancer survivors was significant higher than that of the non-cancer controls after adjusting for related factors. Furthermore, osteoporosis among cancer survivors was higher in elderly subjects (60-69 years : adjusted odds ratio (aOR) 3.04, 95% CI : 1.16-8.00, ${geq}70$ years : aOR 6.60, 95% CI 2.20-19.79), in female cancer survivors (aOR: 7.03, 95% CI: 1.88-26.28), and in a group with lower monthly income (aOR: 3.38, 95% CI: 1.31-8.71). In male cancer survivors, underweight and lower calcium intake were risk factors. Conclusions: These data suggest that the osteoporosis among cancer survivors varies according to non-oncologic and oncologic factors. Effective screening should be applied, and a sufficient and comprehensive management should be matched to individual cancer survivors early after cancer treatment.