The purpose of this study was to examine relationships among selected endogenous factors and sleep patterns during hospitalization in patients with cardiac disease. Participants included 33 male and female patients with myocardial infarction and unstable angina. Wrist actigraph recordings and a computerized sleep algorithm demonstrated that the participants slept for a mean of 424.55 min (SD = 114.52), had a mean sleep efficiency of 77.30% (SD = 15.80), and experienced from 5 to 32 awakenings each night (M = 13.94, SD = 6.29). The mean duration of nighttime awakenings was 9.24 min (SD = 5.60). Self-reports of sleep efficiency, sleep supplementation, and sleep disturbance, using the Verran and Snyder-Halpern (1990) sleep scale, were better than normative data reported for hospitalized patients. The combination of age, gender, New York Heart Association Functional Classification scores (NYHA Criteria Committee, 1964), and prehospitalization sleep loss explained 29% of the variance in objectively measured sleep efficiency and 46% of the variance in duration of nighttime awakenings. These findings suggest the importance of prehospitalization variable as predictors of sleep patterns in hospitalized cardiac patients and provide baseline data for future study.