Oxfendazole, a benzimidazole carbamate, was administered as a 0.5% feed additive to 88 pigs naturally infected with two to four nematode species. Dose rates of 1.5 mg/kg of body weight, 3.0 mg/kg, 3.75 mg/kg, 4.5 mg/kg, 6.75 mg/kg, or 9.0 mg/kg were 100% efficacious against Oesophagostomum dentatum and 99.2% to 100% effective against Ascaris suum. Dose rates of 4.5 mg/kg, 6.75 mg/kg, and 9.0 mg/kg were 92.7%, 98.9%, and 99.5% effective, respectively, against mixed populations of Metastrongylus apri and M pudendotectus. Results were variable with Trichuris suis infections. Efficacy was based on the number of nematodes recovered at necropsy. Palatability and acceptability of the feed additive were good, and adverse reactions following administration were not observed.