Results obtained with a cyclophosphamide, methotrexate, vincristine, 5-FU and prednisone protocol in the treatment of advanced breast cancer are reported. The number of weekly courses proposed by Ansfield was varied. 53% remissions were noted. The effect of the variation introduced was assessed with reference to a much lower incidence of side-effects and a percentage of satisfactory results comparable with that of Ansfield. Nevertheless, it is felt that the treatment in question should be employed as a second choice when more efficacious protocols, such as those including adriamycin, cannot be used or have proved ineffective.