OBJECTIVES: Chronic Myeloid Leukemia (CML) is a rare tumor. In France, the incidence is estimated to be 1/105 inhabitants/years. Imatinib has been approved to treat CML since 2002 but information on routine use, safety and efficacy in unselected “real life” setting is lacking. An observational cohort (LMC) in France was designed to provide data on survival, safety, treatment patterns and quality of life. METHODS: LMC is nationwide, multicenter, observational study on CML patients treated with Imatinib between the availability on the French Market and the end of the 2008. Centers were randomly selected in national files of oncologists, hematologists and internists. The planned follow-up duration was five years. A case report form had to be completed at inclusion and during each follow-up visits. Quality of life was assessed using QLQ-C30 and SF36 questionnaires. RESULTS:  Thrity-nine on 55 selected centers enrolled at least one patient and 387 patients were included (as of June 2009). The median age of disease onset was 59 years. At diagnosis 94% of patients were in a chronic phase and had a low or intermediate Sokal (74%). Before Imatinib, 49% of patients received hydroxuyrea and 16% received interferon. Imatinib initiation was SPC conform: 400 mg per day for 95% of patients. Median treatment duration at inclusion was 25 months. 11% of patients with a follow-up of 1 year iin the study had a modification of te Imatinib dose. Rate of complete molecular response was 37%. With a median follow-up of 3.6 years, 2 years overall survival from first treatment with Imatinib was 96.2% (IC95%:[94.1%-98.4%]). Quality of life of patients was stable. CONCLUSIONS: LMC study is still on ongoing. Current results confirm previous published data on survival in CML treated with Imatinib in an unselected cohort of patients outside a clinical trial.