Prompted by some discrepancies in the report detailing the development of the Composite Scale (CS) of Morningness (Smith et al. 1989) this study replicated the examination of the psychometric properties of the CS on a large sample (n = 424) of health science students. It was confirmed that the mean and range of CS scores previously reported were in error. The finding that the CS has good psychometric properties when used on samples of students was replicated and extended to a smaller (n = 35) sample of individuals working on rotating shifts. CS scores were found to be stable over time and did not change when subjects were exposed to night- and shiftwork.