Laboratory studies were conducted to determine the host preference of the tachinid parasitoid fly Trichopoda pennipes (F.) for the brown stink bug, Euschistus servus (Say), and the southern green stink bug, Nezara viridula (L.). In choice and no-choice tests, 8-fold fewer eggs were laid on E. servus compared with N. viridula. Twenty-four T. pennipes emerged from 100 N. viridula, whereas only 2 larvae emerged from 100 laboratory-parasitized E. servus. Postmortem dissections of egg-bearing stink bugs without larval emergence revealed 20 T. pennipes larvae inside N. viridula but only 1 inside E. servus. These results confirm that T. pennipes prefers N. viridula as a host and is likely only an infrequent parasitoid of E. servus.