One-hundred and sixty-five consecutive immediate breast reconstructions in 157 patients were reviewed. Reconstructions were performed with tissue expanders (53 percent) or immediate gel prostheses (47 percent). Immediate reconstruction was associated with an 18 percent rate of implant loss. Certain risk factors were identified at the p less than 0.05 level using immediate gel implants: failure to achieve complete muscle coverage of the implant, smoking at the time of surgery, initial gel implants of 400 ml or more volume, and age. Expander loss was increased by detaching the pectoralis major (p less than 0.05) and probably by lack of complete muscle coverage in general. Chemotherapy, history of previous smoking, and clinical stage of the carcinoma did not seem to affect reconstructive success. Smoking and patient age should be considered during patient selection for immediate reconstruction. Muscle coverage of the prosthesis should always be attempted. Muscle coverage is mandatory in the smoker. Gel implants of 400 ml or more volume are to be avoided at the initial operation. This approach should enable all surgeons to achieve lower rates of implant loss.