The roles of predators, parasitoids, and a pathogen in effecting natural biological control of cabbage looper (Trichoplusia ni [Hübner]) in San Joaquin Valley cotton were assessed. Life-table analysis indicates that the majority of the generation mortality of cabbage looper occurs during the egg-small larva interval. Observations and experimental evidence strongly indicate that most of this mortality is inflicted by a complex of general predators, primarily adults and nymphs of Geocoris pallens Stal, Nabis americoferus Carayon, Orius tristicolor (White), and possibly larvae of Chrysopa carnea Stephens. These studies, plus evidence from the literature, indicate that the potential for biological control in annual-crop systems is greater than some workers had previously believed, and that the necessity of using only host-specific natural enemies in biological control is a questionable assumption.