Background: Imatinib is capable of inducing durable molecular responses in relapse chronic myelogenous leukemia (CML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT), but it is indefinite whether imatinib therapy is required to maintain this response for patients obtaining complete molecular remission (CMR).We retrospectively reviewed 37 patients with relapse CML post-transplants who were treated with imatinib (n=20) or donor lymphocyte infusion (DLI) (n=17).Aims: To compare the efficacy between imatinib and DLI to the relapse CML post-transplants, and evaluate the results of ceasing imatinib in the patients who had achieved CMR and complete donor chimerism via imatinib treatment.Methods: Once leukemia relapse was diagnosed, immunosuppressants were tapered or discontinued if the patient s condition was acceptable.Those who were in molecular or cytogenetic relapse tapered or discontinued immunosuppressants as a front-line therapy.If these patients were not responsive to this treatment after one month, DLI-or imatinib-based treatments were administrated.Those who were in molecular, cytogenetic or chronic phase (CP) relapse received DLI or imatinib monotherapy as a front-line therapy, and the patients in advanced phase received DLI or imatinib combined with chemotherapy as a front-line therapy.In the DLI-based treatments, patients received DLI once every four weeks until patients obtained complete cytogenetic remission (CCR) or developed graft versus host disease (GVHD).In the imatinib-based treatments, when the patients had recovered donor complete chimerism and had achieved CMR as defined by negative quantitative RQ-PCR at three consecutive time points within a period of 3 months, the patients continued or ceased imatinib therapy according to their willingness.Results: The rate of CMR was 85% and 76.47%, respectively, in the imatinib and DLI group (P=0.509).The treatment-related mortality was 0% and 29.4%, respectively, in the imatinib and DLI groups (P=0.019).Fifteen of the 17 patients obtaining CMR voluntarily ceased imatinib, and did not experience relapse.Eight-year overall survival (OS) was 85% ± 8% and 40.3 ± 12.1% (P=0.017) , 8-year disease-free survival (DFS) was 85%±8% and 40.3 ± 12.1% (P=0.011), respectively, in the imatinib and DLI groups.Conclusions: Imatinib therapy resulted in higher OS and DFS than that of DLI in relapse CML post-transplants.Imatinib maintenance might not be required for patients with relapse CML post-transplants after they achieved full donor chimerism and CMR.