Sickness absence and worksite clinic records of 1,219 nurses employed in a nonsupervisory capacity on permanent day, afternoon, night and rotating shifts were evaluated to assess the health effects of shift schedules. Fixed shift workers tended to take time off for relatively minor ailments, such as colds, headaches and abdominal symptoms, and rarely visited the worksite clinic. Rotating shift workers visited the clinic for minor ailments and were absent because of disorders such as acute respiratory infections and upper gastrointestinal tract symptoms. The authors conclude that rotating shift workers experienced a greater incidence of illness than fixed shift workers, but were less inclined to be absent because of minor ailments. This tendency among shiftworkers to ignore their physical ailments or accept them as a routine consequence of their job, could impede appropriate medical action. The authors recommend the performance of additional research to examine the actual incidence of reported ailments and to assess differences in the recognition and labelling of symptoms based on shift schedules.