PURPOSE: This study was done to determine the level of awareness and self-efficacy and their relationships to osteoporosis among young women. METHODS: The participants were 309 young women living in Seoul. The data were collected using questionnaires from July to September 2009. The Osteoporosis Awareness Scale consists of five areas with a total of 31 questions and the Self-efficacy Scale consists of 18 questions. Data were analyzed using descriptive analysis, t-test, ANOVA, Scheffe test and Pearson's correlation coefficients. RESULTS: The average level for osteoporosis awareness was 2.22, of a possible 4.00 and significant difference were related to participants' previous encounter with any information about osteoporosis, behavior to prevent osteoporosis, experience of weight control, and frequency of vegetable and calcium-rich foods intake. The average level of self-efficacy for osteoporosis was 2.81, of a possible 4.00 and significant difference related to participants' educational level, occupation, behavior to prevent osteoporosis, smoking, method of weight control, regular exercise, and frequency of vegetable and calcium-rich foods intake. There were significant positive correlations among awareness and self-efficacy about osteoporosis CONCLUSION: This study suggests that health care professionals need to provide effective interventions for young women to enhance their osteoporosis awareness and self-efficacy for preventing osteoporosis.