We investigated binding of human parainfluenza viruses (hPIV) types 1 and 3 to the Glycan Array of the Consortium for Functional Glycomics, and binding and release from erythrocytes under conditions where neuraminidase is inactive or active. hPIV1 and hPIV3 bind modifications of Neu5Acalpha2-3Galbeta1-4GlcNAc, including the sialyl-Lewis(x) motif and structures containing 6-sulfogalactose. hPIV-1 and hPIV-3 thus bind typical N-linked glycans in contrast to avian influenza H5 hemagglutinin (15) which binds less common motifs. While the receptor is not the sole determinant of tropism, hPIV or H5 influenza infection of specific cells that express receptors may contribute to their different pathologies.