This article reports on the staff mix and work status of nurses in the adult medical, surgical and obstetrical units in Ontario's teaching hospitals. While staff nurses have extensive career experience, most have been on their unit a much shorter period of time. More than one-third of the nursing staff in the study were employed on a part-time or casual basis, with few indicating an interest in moving into full-time positions. The need for enhanced retention strategies on these units is identified, as well as the development of a better understanding of motivating factors for nurses' regarding full-time, part-time or casual work options.