This report provides data on the amount of time lost and the reasons for time lost from dental practice for a group of 850 clinical practitioners. Results indicate that during 1981 dentists lost an average of 29 days: 2 for illness, 17 for vacation, 5 for professional meetings, and about 5 for other reasons. It was also shown that time off for illness, vacation, and professional meetings increases with the age of the dentist. Differences were noted between general practitioners and specialists, with general practitioners taking more time off for vacation, but less time off for professional meetings than specialists. In the younger and middle-age groups, general practitioners missed more time because of illness than specialists. However, the figures for both groups are much less than the average of five days lost because of medical illness reported for the average worker. A positive relationship between total mean number of days off for all reasons and perceived busyness was also reported. Days off for vacation and professional meetings were the most sensitive to increases in busyness.