The contralateral breast flap is a useful method of reconstruction of the breast and chest wall after the treatment of carcinoma of the breast by surgery and x-ray therapy. Breast tissue is an excellent donor tissue to solve these difficult problems and the only disadvantage is the risk of a second primary breast cancer. Young patients with an identifiable high risk of a second primary tumor are not suitable for this technique. If, however, we confine the operation to the group in whom we are prepared to preserve the breast, with or without a breast reduction, then there is no logical reason why the risk should be any greater in having the residual breast tissue on two sides rather than one. The operation involves the transfer of breast tissue, normally discarded in a breast reduction, to the other side in a two-stage procedure; this is a useful method, both for reconstruction of the breast and also for repair of the chest wall after irradiation damage, particularly in elderly patients. I have found this technique to be suitable in ∼10% of breast reconstructions I have performed; there has been no patient with a second primary tumor over a 15-year period in 60 carefully selected patients.