Abstract: Background and Objective: Breast cancer patients need a variety of skills and abilities to deal with the consequences of the illness. Self-management is one of the operational strategies that leads to disease acceptance, treatment adherence, and improving the quality of life. The use of smartphone applications (apps) can play a pivotal role in the support and self-management of breast cancer patients. This study aimed to identify the educational contents and technical features of a self-management smartphone app for women with breast cancer in Iran. Materials and Methods: This descriptive, cross-sectional study was carried out in 2020. The statistical population of the study consists of 120 women with breast cancer who were selected via simple random sampling. For data collection, a self-designed questionnaire was developed in which validity and reliability of the questionnaire was measured. The statistical analysis of the data was made using the SPSS software. Results: From the breast cancer patients’ point of view, the most important educational contents of the smartphone app. include information acquisition (4.73), lifestyle management (4.65), symptom management (4.43), psychological management (4.01), and compatibility with changes (3.98) respectively. In terms of technical features the most important characteristics were ease of the app. use (4.83), simple visual interface (4.75), security and privacy of information (4.63), reminders (4.55) and the ability to communicate (4.42). Conclusion: For more effective smartphone apps, educational contents and technical features of apps should be designed based on the needs and preferences of patients. To ensure the use and acceptance of the app., developers should design apps that have technical requirements. Keywords: Breast cancer, Smartphone applications, Educational contents, Technical features