This study is an open uncontrolled trial type. The aim of this study is to determine the effectiveness of an educational intervention based on PRECEDE model in improving sleep quality of patients after coronary artery bypass surgery. First, 100 patients refferal to cardiac rehabilitation clinic of Tehran Heart Center having inclusion criteria will be selected and randomly assigned into intervention and control group (50 patients in each group). Selection criteria in the present study is: the patient’s agreement to participate, patients of two genders between 40-80 years of age, only CABG treatment (not combined with valve replacement surgery), current complaint of poor SQ (score>5 of SQ scale), no history of chronic insomnia for at least one year before surgery, body mass index (BMI) ≤35 kg/m2, no indication of receiving treatments for depression and anxiety and no history of a major and serious comorbidity except for the risk factors of arthrosclerosis such as diabetic. During the study period, patients who receive sleeping medications were excluded from the study. Then, pre-test to measure PRECEDE model items (including predisposing, enabling and reinforcing factors regarding sleep) for both groups will be done. After performing pre-test and analyzing the data, educational intervention will be designed according to the pre-test results. Then, educational intervention will be performed for the intervention group. It is considered that the two groups received the provided usual interventions by cardiac rehabilitation clinic. Finally, the two groups are followed 1 month after the intervention and the effect of intervention in sleep quality of patients in the two groups will be assessed.