The nontarget effect of Steinernema feltiae, Steinernema carpocapsae, Heterorhabditis bacteriophora, and three mixed suspensions of two species of entomopathogenic nematodes on the larvae of the twospotted lady beetle, Adalia bipunctata (L.) (Coleoptera: Coccinellidae), and on the larvae of the lacewing Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae), were studied in a laboratory bioassay. The assay was performed at three temperature (15, 20, and 25 degrees C) and at three different concentrations of the suspension (500, 2,500, and 5,000 infective juveniles [IJs]/ml). The larvae of A. bipunctata were more susceptible to nematode attack than the larvae of C. carnea. Four days after treatment, significantly the lowest mortality of A. bipunctata and C. carnea larvae was recorded at 15 degrees C, whereas no significant differences were noted between 20 and 25 degrees C. At 500 IJs/ml, the nematodes had significantly the lowest nontarget effect on the larvae of both aphid predators, whereas no significant differences in this regard were established between 2,500 and 5,000 IJs/ml. We conclude that the entomopathogenic nematodes under investigation exhibit a pronounced nontarget effect on the larvae of both predators mentioned.