© 2022 Institute of Health Promotion and Education.This study was conducted to determine the effects of breast cancer and a breast self-examination training program on women’s knowledge, attitude, and practices relating to breast cancer. The study included 92 women participants and used a randomized controlled experimental research design. The randomization method was used to divide these women into two groups, an experimental (n = 45) group and a control (n = 47) group. A training program was provided to the experimental group, while no such training was provided for the control group. Both groups were followed-up each month for a six-month period. Data were collected using the Personal Information Form, the Breast Self-Examination and Breast Cancer Knowledge Form, and the Breast Cancer Health Belief Model Scale. Differences in the mean level of knowledge, perceived-seriousness, perceived-barriers, perceived-confidence, and health motivation subscale scores of the experimental group were found to be statistically significant for the experimental group, while no such statistical significance was found for the control group (p < 0.05). All women in the experimental group practiced breast self-examination regularly and properly by the sixth month. This study found that planning and implementing a training program based on the Health Belief Model, particularly a regular and one-to-one training and follow-up program, may lead to a regular and proper breast self-examination practice. The training program used in this study made a positive contribution to women’s knowledge, attitudes, and health behaviors regarding breast self-examination.