Based on a series of 516 patients operated between 1976 and 1991, the authors present their experience of the various aspects of immediate breast reconstruction (IBR). A prosthesis was used in the majority of cases (80%) and the essential technical aspect was the creation of a complete muscular compartment, possibly by combining pectoralis major and serratus anterior, latissimus dorsi (5%) and by using an expander (8%) or even a musculocutaneous flap. The rectus abdominis musculocutaneous flap (TRAM, 10%) had the advantage of allowing IBR without a prosthesis. The mastectomy scar plays a major role in determining the final shape of the breast: the skin resection must be modulated according to the site of the tumour. The complications observed (40%), which required removal of the prosthesis in 12% of cases, were either immediate complications (20%), some of which (infections, necrosis, dehiscence) tended to delay adjuvant therapy, or secondary complications, principally grade III-IV contracture (20%). Evaluation of the cosmetic results of IBR in comparison with a population undergoing secondary reconstruction over the same period, did not reveal any significant difference between the two approaches. The authors discuss in detail the oncological and technical arguments for and against IBR and conclude on the psychological advantages of IBR for mastectomised patients.