Donor lymphocytes infusion either alone or with alpha IFN used for treatment of relapse after allogeneic stem cells transplantation (SCT)demonstrated it ́s efficacy in terms of erradication of the malignant clone.We retrospectively analysed and compared the treatment of the group of 13patients(10 males and 3 females)with Ph+ CML (transplantated in 1992-99)who relapsed 3–84 months after SCT.They were treated with DLI alone or in combination with alpha IFN.There were 11 patients in 1st CP 2 patients in 2nd CP. Eight patients received marrow graft from matched sibling donors and 5 patients received unrelated donor transplant.Detection of major BCR/ABL gene expresion was regulary monitored by RT PCR method.Only 5 patients were BCR/ABL negative after SCT 8 patients were BCR/ABL positive more than 3 months after SCT.During monitoring we observed 15 relapses in 13 patients (2 patients relapsed after treatment) Six molecular relapses we documented at med.of 9 months(384)6 molecular and cytogenetic at med.of 30 months(4-86)and only 3haematological relapses at med.12 months(9-90)after SCT.Five relapses were treated by DLI alone 8 relapses were treated by combination of DLI + IFN and 2 heamatological relapses were treated by DLI+STI and DLI+chemotherapy. Median dose of CD3+ were 1x10E7/kg(1,0–1,5)and MNC1,52x 10E8/kg(0,53-2,5).The dose of alpha IFN 3 mil. unit were given 14 days before or l4 days after DLI.In 10/15 relapses(67%)we achieved complete molecular genetic response (BCR/ABL negativity).By use of DLI alone we achieved 3 molecular remisions of 5 relapses (60%) in median time of 7 months. Two patiens obtained only reduction of BCR/ABL level but they remain positive 44 resp. 55 months after DLI.In the group of patients treated by combination DLI + IFN we observed complete remision (CR) in 7 of 8 relapses (87%) in med. 2,5 months. One patient in haematological relapse died due to complications of the treatment (aplasia). Two other responded to therapy DLI+ STI, DLI + chemoterapy, but the later one is at present time in second relaps. Acute GVHD ocured in 6 of 13 patients (2 x I. grade 2 x II. grade,1 x III.grade and 1 x IV. grade)and limited chron. GVHD by 1 patient. Toxicity of combination DLI + IFN was higher than the toxicity of DLI alone. The overal survival of the cohort of 13 patients is 92%(l2/l3) with median survival 53 months (29-114). Our results shown that combination DLI + alpha IFN is probably more effective, but more toxic than DLI alone.