A COOPERATIVE STUDY of a treatment of myeloma by 21 institutions has been in progress for four years.1A uniform protocol, criteria, and data flow sheets have been followed and evaluated by the committee. Comparison survival data with previous forms of treatment was obtained in an ancillary myeloma study by the same cooperative group in the same institutions.2Cyclophosphamide (Cytoxan) was selected as an alkylating agent suitable for use in a low oral dose, longrange program. These results are based on a study of 165 patients who received the drug for at least 60 days (an "adequate trial"). Twenty percent (42) of the patients who started the study did not reach adequate trial status because of death (17), complications (8), or loss to follow-up (17). Materials and Methods Participating investigators placed on study as many patients as possible from their respective institutions. The diagnosis of multiple myeloma was