Species of subfamily Anthocorinae from alfalfa, potato and wheat fields in three different regions of the East Azerbaijan province were collected and identified during 2002-2004. Taxonomic characteristics of different parts of the body as well as male paramere were employed. Four species of Orius niger Wolff, O. minutus (Linnaeus), O. horvathi (Reuter) and Anthocoris pilosus (Jakovlev) were detected in alfalfa and potato fields that fed on thrips like Thrips tabaci, aphids such as Aphis craccivora Koch and Acyrthosiphon pisum Harris as well as mites such as Tetranychus urticae Koch. In wheat fields, only Orius niger was observed which feeded on thrips like Haplothrips tritici Kur. as well as aphids such as Schizaphis graminum Rondani and Sitobium avenae F.. An identification key to the species is presented. Among identified species, O. niger was dominant in alfalfa, potato and wheat fields in all the three different regions of the East Azerbaijan province. Also population density of O. niger in wheat fields along with four species of Anthocorinae in potato and alfalfa fields was higher at reproductive stages of the three crops than that at their vegetative stages, in the three studied regions.
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