CML Ph ¹ ⁺ formed malignant transformation of pluripotent hematopoietic stem cells whose autonomous proliferation occurs same malignant clone of altered cells. Initially developed as a chronic phase with an average duration of 3 - 4 years, and then at the acute phase or acute leukemia. All cases of malignancies, 3 % is related to leukemia. CML Ph ¹ ⁺ makes 20 % of all leukemia. The incidence is approximately one new case / 100 000 per year. Today is a very effective therapy for the prevalence of CML and Ph ¹ ⁺ in annual increments of 4.5. The aim of this study is to assess molecular response (major and complete) in patients with Ph ¹ ⁺ CML. Identify the difference and efficacy of therapy in patients treated with first and second generation tyrosine kinase inhibitors. The sample is defined by the total number of patients treated with tyrosine kinase inhibitors at the Department of Hematology at University Hospital in Split. Incorporating a retrospective study in which data were used in the period from 2004 to 2014 year. The study included 30 patients, of which 18 are male (60 %) and 12 females (40 %). The median age was 58 years. The oldest patient was 88 years at diagnosis, the youngest 23 years old. When diagnosing two patients were in accelerated phase disease (7 %), 28 patients in the chronic phase of the disease (93 %). Results of the analysis to patients who are being treated in hospital in Split are in line with the expected therapeutic response. They are similar to the results of clinical trials (Studies ENESTcmr, IRIS study and ENESTnd study). Thanks to these targeted molecular drugs life of patients with Ph ¹ ⁺ CML who achieve optimal therapeutic response is similar to the life of a healthy population of the same age. Today, the aim of this effective therapy should be to achieve a deep molecular response, because it significantly reduces the risk of adverse events: progression to accelerated phase / blast phase and the occurrence of mutations.