Patients undergoing a bone marrow harvest have traditionally been hospitalized for several days. Recently, the feasibility of outpatient bone marrow harvesting has been reported. We retrospectively examined the results of 485 patients undergoing an outpatient bone marrow harvest from 1989 to 1993. One hundred and eleven patients were normal donors and the remaining patients were undergoing a bone marrow harvest for autologous transplants. Four hundred and eighty one patients (99%) were discharged within 12 h of the harvest and none have developed long-term complications from the procedure. We additionally analyzed harvest yield with respect to time under anesthesia and underlying diagnosis. Surprisingly, time under anesthesia correlated negatively with harvest yield (P = 0.0001). After adjusting for volume harvested and time under anesthesia, harvest yield was higher in normal donors and patients with breast cancer than for patients with non-Hodgkin's lymphoma and Hodgkin's disease. We conclude that outpatient harvesting is safe. The negative correlation of time under anesthesia with harvest yield may be a result of variables which are difficult to quantify, such as bone marrow microenvironment.