OBJECTIVE: To study various aspects of sleep quality and sleep patterns prior to and after coronary artery bypass surgery and their implications for 5-year survival. METHODS: All patients from western Sweden who underwent coronary artery bypass grafting (CABG) between 1988 and 1991 (n = 2,121) received a questionnaire addressing sleep habits prior to and I year after surgery.Various symptoms and habits related to sleep at the two evaluations were compared. Symptoms and habits related to sleep prior to CABG were then related to 5-year survival. RESULTS: In all, 1,224 patients took part in the evaluation. A highly significant improvement was observed with regard to the following symptoms and habits related to sleep: feeling refreshed upon awakening, feeling tired during daytime, waking up with headache, nightmares, sweating during night time, medication for pain relief at bedtime, involuntarily falling asleep during daytime, apnoea during sleep and mouth dryness during the night. Various symptoms and habits associated with sleep prior to CABG were generally not strongly related to prognosis. Exceptions were feeling refreshed upon awakening and infrequent consumption of pain relief medication at bedtime which both were associated with an improved long-term survival. CONCLUSIONS: A variety of symptoms associated with sleep improve highly significantly after CABG.The occurrence of these symptoms prior to CABG do not generally seem to influence the long-term prognosis.