We measured baseline serum mannose binding lectin (MBL) levels in 91 patients with childhood leukemia to determine their predictive value for the development of febrile neutropenia or specific infections. Median MBL levels did not differ significantly between patients who developed febrile neutropenia, bacterial infection, or disseminated fungal infection and those who did not. In addition, low MBL levels were not associated with an increased cumulative incidence of infection or with a shorter time to first infection. This preliminary study suggests that baseline MBL levels may not be clinically useful to identify pediatric leukemia patients who are at increased risk of infection. Additional studies are required to determine whether serial MBL measurements may be valuable for this purpose. Pediatr Blood Cancer 2008;50:866–868. © 2007 Wiley-Liss, Inc.