Behaviors such as an appropriate diet, physical activities, health responsiveness such as attending diagnoses and treatment recommendations, preventing from known health risks such as smoking, allocating time to rest and peace and managing stress are related to health-promoting lifestyles (HPLs). The objective of the current study was to determine the relationship between HPL and body mass index (BMI) of male nurses based on demographic variables. A descriptive correlation survey was conducted among 108 male nurses using the nonprobability sampling technique. Data were gathered through a questionnaire consisting of two parts: demographic characteristics and Pender’s health promotion questionnaire. Data were analyzed by presenting measures, mean, standard deviation, independent t-test, Pearson’s coefficient correlation, and one-way analysis of variance (ANOVA), using SPSS version 22. The mean score for male nurses’ HPL was good (3.13). The highest mean was from spiritual growth (3.48) and the lowest was from physical activity (2.69). Approximately 24.07% participants were overweight and obese. The mean of HPL in normal-weight people was better than that of obese ones. Participants did not pay much attention to their family’s health-promoting behaviors. They also were exposed to occupational hazards, including psychological (47.2%), ergonomic (21.7%), physical (20.8%), and biological hazards (10.4%). There was no significant relationship between age ( p = .14), educational level ( p = .95), marital status ( p = .32), job experiences ( p = .17), and HPL variables. As health providers, nurses should both provoke patients to attain their health and to strive to maintain and sustain their own health, especially for obesity prevention. From society’s perspective, a nurse is one who knows more and acts better; therefore, paying attention to nurses’ HPL is a professional and social expectation.