Reliable information on cost and value in microsurgery is not readily available in the literature. Driving factors for cost, determinants of complications, and cost-reduction strategies have not been elucidated in this population, despite such progress in other areas of medicine. Clearly, the time-consuming and costly nature of this endeavor demands that appropriate indications and patient management be delineated; to operate proactively in this cost-conscious time, financial and outcome determinations are critical. One hundred seven consecutive free-tissue transfers performed from 1991 to 1994 by a single microsurgeon were studied. Retrospective chart review for clinical parameters was combined with analysis of hospital costs and professional charges. Operating room and anesthesia costs were based on a microcost analysis of actual operating room time, materials, labor, and overhead. Other patient level costs were generated by Transition 1, a hospital cost-accounting system. The following issues were addressed: (1) flap survival; (2) total costs and length of stay for all free flaps; (3) payments received from various insurers; (4) breakdown of operating room costs by labor, supplies, and overhead; (5) breakdown of inpatient costs by category; (6) additional costs of complications and takebacks; (7) factors associated with complications and flap takebacks; and (8) cost-reduction strategies. Mean free flap operating room costs (exclusive of professional fees) ranged among case types from $4439 to $6856 and were primarily a function of operating room times. Elective patient cases lasted a mean 440 minutes. There was a large disparity in reimbursement: private insurers covered hospital costs (not charges) completely, whereas Medicare paid 79 percent and Medicaid only 64 percent. Length of stay, operative procedures, and complications had the greatest influence on inpatient costs in this group of free flap patients. Potential cost savings as a result of possible practice changes (e.g., shortening intensive care unit stays and avoiding staged operations) can be predicted. This analysis has caused a revision in these institutions' practice patterns and lays the foundation for planned outcome studies in this population.