Fcγ receptorIIIa (FcγRIIIa) polymorphism was considered to influence clinical response to therapeutic monoclonal antibody (MAb) against cancer, which is suggested to affect MAb binding and MAb-dependent NK cell-mediated cytotoxicity. The purpose of this study was to examine the FcγRIIIa gene polymorphisms in healthy children and in children with hematological malignancy, and to explore its possible effect on MAb in children with hematological malignancies. 43 healthy children (H) and 20 pediatric patients with hematological malignancies (HM) were enrolled in this study. DNA was isolated from peripheral blood, and then nest-polymerase chain reaction-restriction fragment length polymorphism (nest-PCR and PCR-RFLP) was used to determine the FcγRIIIa-158 genotypes in each groups of subject, digested fragments were subjected to electrophoresis on 15% PAGE. The results showed that there were a higher frequencies of FcγRIIIa-158V/F in H and HM group (72.1% and 75.0% respectively), the frequencies of FcγRIIIa-158V/V were 27.9% and 25.0% in H and HM group respectively, but there was no FcγRIIIa-158F/F in the two groups. No significant difference in distribution of the FcγRIIIa-158 genotype was found between HM and H groups (p > 0.05). It is concluded that FcγRIIIa-158V/F is more frequent, while FcγRIIIa-158V/V is less, but FcγRIIIa-158F/F is very rare in both groups. No significant difference of FcγRIIIa polymorphism distribution is found between healthy and hematological malignancy groups.