Context: Brachytherapy is one of the cancer treatment modalities. Like any treatment, it can produce acute and delayed side effects. Unfortunately, patients getting brachytherapy experience many side effects that may affect their all quality of life aspect. So, nurses working in radiotherapy settings must be confident about their knowledge, competence, and technical skills. Therefore, holding continuing education programs for nurses is necessary. 
 Aim: This study aimed to determine the effect of brachytherapy safety education on radiology nurses' knowledge, attitude, and performance.
 Methods: Quasi-experimental one group pre-posttest design was utilized to achieve the aim of this study on nurses working on Ayadi El Mostakabal Hospital, Alexandria, Egypt. Four tools were used to collect the necessary data. The self-administered questionnaire was designed to collect the necessary data about the nurses. Radiology Nurses’ Knowledge Assessment Questionnaire to assess nurses' knowledge regarding nursing interventions for patients getting brachytherapy. Nurses’ Performance Observational Checklist to assess the actual nurses’ performance provided to patients getting brachytherapy. Radiology Nurses' Attitude Assessment Scale (RNAAS) measures nurses' professional attitude and the influence of safety training programs on nurses' attitudes.
 Results: There was a statistically significant difference between nurses' knowledge, performance, and attitude between the initial assessment, immediate, two weeks later, and three months of educational program implementation at p=0.001. Regarding the relationship between studied nurse's knowledge and their characteristics, there was a relationship found between nurses’ knowledge in the initial assessment and their age, marital status, and nurses’ years of experience at p=0.001, 0.002, and 0.0, respectively. While in the post-program implementation, the only relation was found between the nurses’ knowledge score and years of experience p=0.007, 0.053, and0.011 in immediate, two weeks later, and after three months of program implementation, respectively. There was no relation found between nurses' performance and their characteristics throughout program implementation phases.
 Conclusion: The current study findings concluded that radiation safety education for nurses regarding brachytherapy resulted in a statistically significant improvement in nurses' knowledge, performance, and attitude. Periodic and consistent update in-services training of nurses to improve their knowledge and practice enforces nurses to follow the approved guideline. Future studies are recommended to investigate nurses' knowledge and performance of radiation protection in the general ward or specialized departments.