BackgroundThe COVID-19 virus has had wide-ranging effects on all healthcare systems and a direct impact on all areas of human life in all countries around the world. Therefore, it is necessary to take preventive actions to reduce the prevalence and severity of the complications associated with this disease. The purpose of this study was to explain the dimensions of adopting general self-care behaviors (mask-wearing, social distancing, hand hygiene, and home quarantine) for preventing COVID-19 based on the theory of planned behavior (TPB) in cardiovascular patients.MethodsThis was a descriptive-analytical study conducted with the participation of 420 patients referring to health and treatment centers of Ahvaz, southwest of Iran, in 2022. Sampling was done using a non-random (convenience) method. The data collection tool was a questionnaire containing items addressing demographic characteristics, questions related to the TPB, and questions dealing with the adoption of everyday self-care behaviors against contracting COVID-19. Data were analyzed using descriptive and inferential statistical methods (prevalence, mean, standard deviation, Pearson’s correlation coefficient, and linear regression) in SPSS version 25.ResultsThe results of this study showed that the rate of adoption of self-care behaviors against COVID-19 among cardiovascular patients was moderate. The results also showed that among the constructs of the TPB, Perceived behavioral control, Subjective norms, and Perceived behavioral intention were the most important predictors of adopting self-care behaviors among cardiovascular patients with a change variance of 46%.ConclusionsThe results of the present study have implications for health and treatment policy makers as well as planners of educational and behavioral interventions aimed at promoting the adoption of self-care behaviors against COVID-19. In this respect, managing and institutionalizing desirable behaviors among cardiovascular patients could be beneficial from economic, social, and health-related aspects.