Six species of the syringophilid mites belonging to the genus Syringophiloidus Kethley, 1970 (Acari, Prostigmata) are recorded from eight avian hosts from USA. Four new species are described and illustrated: S. molothrus sp. nov. from the Brown-headed Cowbird Molothrus ater (Boddaert) (Passeriformes, Icteridae), S. carolae sp. nov. from the Acorn Woodpecker Melanerpes formicivorus (Swainson) (Piciformes, Picidae) and from the Northern Cardinal Cardinalis cardinalis (Linnaeus) (Passeriformes, Cardinalidae), S. sialius sp. nov. from the Western Bluebird Sialia mexicana Swainson (Passeriformes, Turdidae), and S. thryothorus sp. nov. from the Carolina Wren Thryothorus ludovicianus (Latham) (Passeriformes, Troglodytidae). The previously described species S. motacillae Bochkov et Mironov, 1998 is new for USA. Two host species, the American Robin Turdus migratorius Linnaeus (Turdidae) and the Steller’s Jay Cyanocitta stelleri (Gmelin) (Passeriformes, Corvidae), are new for S. presentalis Chirov et Kravtsova, 1995.