We conducted a review of patient medical records to assess treatment response patterns and prognostic indicators of response among chronic myeloid leukemia (CML) patients in the United States, the United Kingdom, Germany, and Japan. All 1,063 patients selected met the following inclusion criteria: aged 18 or older and in chronic phase at the time of diagnosis, Philadelphia chromosome and/or BCR-ABL positive, received first-line treatment with imatinib, and not enrolled in a randomized clinical trial during the period of retrospective review. Multivariable logistic regression models were used to evaluate prognostic indicators of complete hematological response (CHR), complete cytogenetic response (CCyR), and complete or major molecular response (C/MMR). Among patients treated with first-line imatinib, CHR at three months, CCyR at 12 months, and C/MMR at 18 months were observed in 53, 53.1, and 57.8 % of patients, respectively. Among patients treated with second-line dasatinib or nilotinib, CHR was achieved at three months in 49 and 42 %, CCyR at 12 months in 32 and 23 %, and MMR at 18 months in 30.5 and 26.1 % of patients, respectively. Prognostic indicators of first-line response included age, race, and Sokal score. For second-line treatment, duration of first-line hematological response and choice of drug used were also significant.