From January '85 to April '87, 81 patients (pts) with diffuse intermediate and high-grade non-Hodgkin's lymphomas were treated with the ProMace/MOPP protocol in a large Italian Cooperative Study Group (NHLCSG). Criteria for entry into the study included: no prior therapy, stage III-IV or stage II with bulky disease and/or B-symptoms, age below 65. 79 pts were evaluable for response. Almost all pts received six courses of chemotherapy, plus radiotherapy on bulky disease. 53 pts (67%) achieved complete remission (CR), 7 (9%) partial remission (PR), 4 (5%) were considered stable disease (SD) and 15 (19%) progression disease (PD) with 5 of them died early during treatment. The actuarial overall survival (OS) and disease free survival (DFS) are respectively 54% at 61 mos and 62% at 41 mos. The median follow-up from the end of therapy is 56 mos (range 40-68). Until now 20 pts (38%) relapsed on a median time of 8 mos (range 2-21) from CR. These data allowed to us to consider this regimen as effective as the third generation protocols also taking into account the multicenter basis of this study. With the aim to evaluate the impact of the third generation regimen on the outcome of these pts, a randomized study has been performed comparing ProMACE-MOPP with the third generation regimens MACOP-B. Therefore, from 1988 up to now, 206 pts with similar clinical and histological characteristics, have been enrolled in the two arms. No differences in terms of CR and DFS have been registered between the two treatments, with roughly the same toxicity. An analysis of prognostic factors in the larger series of pts treated with ProMACE-MOPP in the first and in the second study (167 pts) was performed. On these basis it seems reasonable that our next step would be to candidate these poor prognosis pts to a new therapeutic strategy which included the use of ABMT and/or PBSC transplantation as first line.