Background: Impaired sleep may be a mediator of prognosis in chronic cardiovascular disease. Early sleep hygiene interventions integrate evidence-based practice to improve cardiovascular status. Purpose: To examine the effect of sleep hygiene on sleep quality, anxiety and incidence of cardiac dysrhythmia, among patients with myocardial infarction (MI). Design: Study /control group quasi‐experimental design was used. Sample: The study was carried out on a purposive sample of 100 adult patients with acute myocardial infarction in CCU. Setting:  Coronary care units at Menoufia University Hospital, Egypt. Instruments:  1) A semi-structured socio-demographic and medical data sheet; 2) Pittsburgh Sleep Quality Index (PSQI); 3) Insomnia Severity Index (ISI); 4) State-trait Anxiety Inventory (SAI); and 5) follow-up sheet for the number of premature ventricular and atrial contractions (PVCs & PACs). Results: There is a highly statistically significant reduction in the total mean score of PSQI in the study group (4.72±1.33) compared to the control group (16.82±1.95) (p<0.000) post-intervention. Also, there was a highly statistically significant decrease in the mean score of ISI in the study group (8.72±7.28) compared to the control group (15.98±7.56) (p=0.000) post-intervention. The study group had a statistically significant decrease in the total mean score of anxiety post-intervention (36.30 ± 9.17) compared to the control group (42.82±11.96) (p=0.003). Additionally, A statistically significant decrease was found post-intervention in the number of PVCs and PACs in the study group (2.61±1.77 & 1.39±0.87) compared to the control group (5.020.49 and 2.991.33); the P values were 0.002 and 0.003, respectively. Conclusion: Sleep hygiene interventions have a positive effect on improving sleep quality, reducing anxiety and insomnia, and decreasing the number of PVCs and PACs in patients with MI. Recommendation: Develop clinical practice guidelines for critical care nurses to apply sleep hygiene interventions as standard care for patients with MI.