Livin, a member of the inhibitor of apoptosis proteins, has been considered to be a poor prognostic marker in malignancies. However, little is known about the clinical relevance of Livin expression in childhood acute lymphoblastic leukemia (ALL). In this study, the expression of Livin was analyzed in 222 patients with childhood ALL using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to investigate a possible association with the clinical features at diagnosis and treatment outcomes. Both Livin expression rates and expression levels were higher in patients with favorable prognostic factors. The expression rate was also higher in patients with a favorable day 7 bone marrow response to induction chemotherapy (P<.001). The Livin expression was related to the absence of relapse (P<.001). Similarly, the relapse-free survival rate (+/-95% CI) was higher in patients with Livin expression than in patients without Livin expression (97.9%+/-4.0% versus 64.9%+/-11.8%, P<.001). Multivariate analysis for relapse-free survival demonstrated that Livin expression was an independent favorable prognostic factor in childhood ALL (P=.049). This study suggests that Livin expression is a novel prognostic marker in childhood ALL and thus needs to be incorporated into the patient stratification and treatment protocols.