This study aimed to determine the relationship between the perception of self-efficacy and early post-operative symptoms in patients who had undergone coronary artery bypass graft (CABG) surgery with median sternotomy. All patients aged over 18 who had undergone CABG surgery for the first time with median sternotomy and who agreed to participate in the research. An “Individual Introduction Form”, the “Barnason Efficacy Expectation Scale: Cardiac Surgical Version”, and the “Heart Surgery Symptom Inventory” were used for data collection. Student t-test, One-Way ANOVA, Kruskal Wallis test, Man-Withney U test, correlation, and multiple linear regression analysis were used for data analysis. The means age of the patients who had undergone CABG surgery was 56.58±11.83. The severity of symptoms perceived by the patients was evaluated with HSSI and the mean scale score of the patients was 45.71±26.51. In the study, the self-efficacy score of the patients was 42.33±7.74. The level of self-efficacy of the patients increased as the mean age increased. Although the patients’ levels of self-efficacy were high after coronary artery bypass graft surgery, the severity of their symptoms was moderate. Marital status, cohabitants, and family history of cardiac disease were found to affect the severity of patients’ symptoms.