During a 10-year period (1980 through 1989), 28,953 patients were admitted to our Clinic of Digestive Surgery, Geneva, Switzerland. Two thirds of them were operated on, and one third were treated conservatively. Symptomatic pulmonary embolism (PE) was recorded in 90 patients (0.31%; 95% confidence interval, 0.25% to 0.38%) during their hospital stay. Within 30 days of hospital discharge, 29 patients were readmitted because of PE (incidence of delayed PE, 0.10%; 95% confidence interval, 0.07% to 0.14%; total incidence of PE, 0.41%; 95% confidence interval, 0.34% to 0.49%). In the operated-on group, the delayed embolic events occurred a median of 6 days (range, 2 to 25 days) after discharge and 18 days (range, 6 to 35 days) after surgery. Delayed PEs were more frequent after so-called low-risk surgery. Thus, the rate of postoperative PE increased by 30% when PEs occurring within 30 days of hospital discharge were considered, and this provides a useful basis for prolonged prophylactic measures after hospital stay.