The Fcgamma receptors CD16A and CD32A connect the innate and the adaptive immune responses by transmitting activating signals to natural killer lymphocytes and myeloid cells upon recognition of antigen-immunoglobulin G (IgG) complexes. Two allelic dimorphisms of these receptors, valine/phenylalanine-158 of CD16A and histidine/arginine-131 of CD32A, modulate their affinity for certain human IgG subclasses. Furthermore, these polymorphisms are clinically relevant because they modify the susceptibility, the clinical course and the response to therapy of several human diseases. Genotyping of CD16A and CD32A alleles, encoded by FCGR3A and FCGR2A, respectively, is complicated by the fact that they both belong to families of highly homologous genes. In this study, we present an original method for genotyping the FCGR3A and FCGR2A dimorphisms based on the technique of polymerase chain reaction with confronting two-pair primers. The new method simplifies the analysis of FCGR3A and FCGR2A because the two alleles of each gene are detected simultaneously in a single reaction and separated, with no further manipulations, by their different electrophoretic mobilities in regular agarose gels. We also present the CD16A and CD32A genotypes of cells from the Tenth International Histocompatibility Workshop, which can serve as a reference cell panel for investigating the influence of CD16A and CD32A polymorphisms on human health.