Species of Orius (Anthocoridae), Geocoris (Lygaeidae), and Nabis (Nabidae) are among the more abundant predatory Heteroptera found in North American agroecosystems, their relative abundances varying among crops. Other groups encountered in agroecosystems include species of predatory Pentatomidae, Reduviidae, Miridae, and Berytidae. Among these taxa, Orius spp. appear to occur in significant numbers across the widest range of crops in North America. Overall, predatory Heteroptera appear to be more abundant in field crops than in most vegetable, fruit, or nut crops. Comparisons of published faunistic studies of major field crops indicate that alfalfa, cotton, and soybean harbor the most diverse and abundant predatory heteropteran faunas. Relatively large species (>10 mm body length), such as predatory pentatomids and reduviids, are less abundant in agroecosystems than smaller heteropteran predators such as anthocorids and nabids. Life history traits of common heteropteran predators are discussed with regard to potential implications for natural biological control. It is suggested that the most important role of this group is their reduction of intragenerational survivorship of certain types of pest species.