Resource costs, which are the costs to the hospital of providing a service, were measured for 154 patients who underwent mastectomy and immediate breast reconstruction with TRAM flaps. Unilateral and bilateral reconstructions were evaluated separately. The resource costs required to perform mastectomy and reconstruction with free TRAM flaps were then compared with those required when conventional TRAM flaps were used. The mean total resource cost in the free TRAM group was slightly higher than in the conventional TRAM group, but the difference was small (4.1 percent) and not statistically significant (p = 0.290). The mean resource cost of performing bilateral mastectomy and reconstruction was higher than that of unilateral mastectomy and reconstruction, but the difference was only 5.0 percent (p = 0.046). This study shows that the cost to an institution of providing breast reconstruction with free TRAM flaps is not significantly higher than that of performing reconstruction with conventional TRAM flaps. Also, our findings show that the resource costs of performing bilateral mastectomy and reconstruction are not much higher than those of treating only one breast.