The purpose of this study was to investigate whether platelet indices [mean platelet volume (MPV) and platelet distribution width (PDW)] could serve as diagnostic tools for screening or as surrogate marker for follow-up in children with leukemia. Blood samples were obtained from 47 patients with leukemia at diagnosis before chemotherapy (mean age: 67 mo; 30 males and 17 females) and from 47 healthy controls (mean age: 59 mo; 27 males and 20 females). We measured the blood platelet indices using an automated counter. MPV was higher in the leukemia group, but it was not statistically significant. However, PDW was significantly lower (P<0.001) in leukemia group. There was no significant difference in the MPV or PDW in patients with acute lymphoblastic leukemia versus acute myeloblastic leukemia. In conclusion, we found no significant difference in the MPV between the 2 groups. PDW proposed as indicators of certain pathologic conditions and it seems possible to use PDW as screening. However, platelet indices (MPV and PDW) cannot be used as indicator to discriminate between the subtypes of leukemia in children. The potential role of platelet indices in leukemia remains to be investigated by a multi-institutional level to verify the possible clinical significance of this finding.