LIM domain only-2 (LMO2) is an important regulator of hematopoietic stem cell development. LMO2 protein is expressed in all three hematopoietic lineages precursors of the hematopoietic system, and its expression has been shown to decrease gradually during differentiation. Chronic myeloid leukemia (CML) is a malignant clonal myeloproliferative disorder in which the terminal differentiation is not altered until the appearance of an accelerated or blast phase. We examined whether LMO2 protein expression can predict outcome CML patients undergoing tyrosine kinase inhibitor therapy, imatinib mesylate (IM). Immunohistochemistry on bone marrow biopsy material for LMO2 protein was performed in 47 CML patients. We report that the LMO2 protein expression is correlated with improved hematologic remission and overall survival in the CML patients treated with IM. The immunohistologic analysis of LMO2 protein expression may become a predictive factor for anticipating the treatment responses of CML patients.