Background: Sleep patterns of patients who admitted the intensive care unit (ICU) after surgery have shown fragment and disturbed sleep during early postoperative days. However, there is less information about sleep status in patients after transferred to a surgical ward from the ICU. The aim of this study was to evaluate the sleep patterns in elderly patients after cardiac surgery including stay in both the ICU and surgical ward. Methods: Twelve patients aged ≥ 65 years were examined for 3 days before and 6 days after surgery. We used to examine sleep quality an actigraph and the Oguri-Shirakawa-Azumi sleep inventory (version for patients of middle age and older) for sleep. Results: Total sleep time was significantly decreased postoperative day 3 (median, 368.5 min) and 4 (median, 433.5 min) than before surgery (median 526.0 min) (p<0.05). Nocturnal sleep time showed significant decreases from preoperative values until postoperative day 1-4 (p<0.05). Duration of longest sleep was significantly decreased postoperative day 1-3 than before surgery (p<0.05). Sleep scale (sleep length and maintenance of sleep) scores indicated a decline in sleep quality on POD3 compared with preoperative values (p<0.05). The sleep disturbances did not reach preoperative levels until at least POD4. Conclusions: The sleep disturbances persisted not only throughout patients’ ICU stay but also after they had been discharged from the ICU. Therefore, close collaboration between surgical ward and ICU nurses are the key to provide more appropriate and early interventions.