OBJECTIVES: Chronic Myeloid Leukemia (CML) is a myeloproliferative disease associated with a chromosomal translocation (Philadelphia chromosome). Since 2003 life-long treatment by Tyrosine Kinase Inhibitors (TKIs) have dramatically improved survival. The objective of this study was to predict the characteristics of the population under TKI treatment at the horizon 2015. METHODS: An epidemiological model was developed over the period 2003-2015 on first and following line therapies, combining demographic, incidence, prevalence, survival data and probability of resistance or intolerance in each line. Data were derived from published randomized clinical studies. The model was tested over the period 2003-2009 by comparison with retrospective market data and then extrapolated to the period 2010-2015. RESULTS: At the time of the first TKI launch (imatinib) in 2003, a prevalent group of 1,878 patients started treatment. Second-generation TKIs dasatinib and nilotinib were then made available in France between November 2007 and May 2008 as second line therapy, and potentially in mid-2011 as first line. Despite a stable annual number of 600 incident cases (1.25 x10-5) of CML eligible for a TKI first line treatment, the total number of patients under treatment increased to 7260 in 2010 (a 3.9-fold increase since 2003) of which 1083 were in second line (15%). The extrapolation model predicted a total of 10,069 treated patients in 2015 of which 1,618 in second line (16%) representing a 39% 5-year increase. CONCLUSIONS:  The dramatic overall survival benefit associated with TKIs was a key factor for explaining the growth of the CML treated population aside from the emergence of second line therapies.