In Tunisia, self-medication is a common practice, and there is a continual rise in the prevalence of cardiovascular disease. Given the lack of data on the self-medication practices (SMPs) among cardiovascular patients in this area, the present study aimed to identify the prevalence and determinants of SMPs among cardiovascular patients in the city of Béja. A community-pharmacy-based survey was conducted among selected cardiovascular patients in Béja, Tunisia, from May 2021 to June 2021. Data were collected using a self-administered questionnaire provided by pharmacists during in-person surveys with patients. Descriptive statistics were used to summarize the data, while Fisher’s exact test was used for categorical variables, with the significance level set at p < 0.05. The frequency of self-medication among the 150 respondents was 96%; 70.14% of participants reported that the primary reason why people engage in self-medication is the existence of an old prescription. The most prevalent conditions leading patients to self-medicate were headaches (100%), fever (83.33%), toothache (65.97%), and dry cough (47.92%). The most frequently self-administered drugs were paracetamol (100%), antibiotics (56.94%), and antitussives (47.92%). The results of our study indicate that SMPs among Tunisian cardiovascular patients have a high prevalence. With this in mind, healthcare practitioners should ask their patients about their self-medication practices and advise cardiovascular patients about the risks and benefits associated with this practice.