Purpose: We aimed to investigate the status of POM121 gene expression, which is one of the nuclear pore proteins in childhood acute lymphoblastic leukemias (ALL), compared with the normal population, and its relationship with prognosis and other clinical findings. Materials and Methods: Fifty-nine patients with ALL followed up and treated between January 2008 and November 2013, and 36 control subjects were included in the study. A real-time PCR method was used to detect POM121 gene expressions. Results: The mean value of POM121 expression was 3.75±2.91 in ALL patients and 3.32±3.76 in the control group. The 3 and 10 year overall survival (OS) was better in ALL with lower POM121 expression (77%, 70% versus 68%, 58%, respectively). Although the OS was better in B-ALL patients, with lower POM121 expression (84%, 75% versus 54%, 46%, respectively), in T-ALL, in contrast, the OS results were better in patients with a higher POM121 expression (90%, 90% versus 60%, 60%, respectively). Patients with a higher POM121 expression than the mean of the control group and who had relapse and central nervous system involvement had statistically significantly lower OS results in the 3rd and 10th years (16%, 0% versus 84%, 78%, respectively). Conclusion: High POM121 expression negatively affects the prognosis in patients with ALL. This is a study to show the relationship between POM121 expression and prognosis in childhood acute lymphoblastic leukemias, POM121 function will be clarified further with more comprehensive studies.