Prognostic factors in patients with chronic myeloid leukaemia (CML) treated with conventional treatment include age, spleen size, platelet count, blood percentage of blasts, basophils and eosinophils, and cytogenetic abnormalities besides the Philadelphia chromosome. The value of traditional clinical and laboratory features to identify patients at increased risk of imatinib failure has not been established yet. Biological markers such as gene expression profile, v-crk sarcoma virus CT10 oncogene homologue (avian)-like (Crkl) phosphorylation or expression of imatinib transporter proteins have been shown to be useful to predict the response to imatinib. In practice, the response obtained at different time points from the initiation of imatinib is employed to predict the patient's outcome, with this especially applying to cytogenetic response. The prognostic relevance of early molecular response to imatinib has also been pointed out. Prognostic factors for response to second-generation tyrosine kinase inhibitors (TKI) after imatinib failure are currently being investigated.