There is increasing public concern over the use of subtherapeutic antibiotics in livestock feed. Some companies are exploring alternative feed supplements, such as oregano. A study was conducted at the ISU Swine Nutrition Farm to study the effects of oregano-supplemented diets on nursery pig performance. A total of 80 pigs were used in the study and were weighed weekly for four weeks. Five treatment diets were fed: control (no additive), carbadox, 0.5%, 1.0%, and 2.0% added oregano. Pig performance was calculated as ADFI, ADG, and FE. The data were analyzed using the GLM model of SAS. Overall, feeding oregano diets to nursery pigs resulted in no improvement in performance. Also, the carbadoxsupplemented diet did not improve pig performance compared with the non-supplemented diet. Research could be continued through finishing. There may be an initial period of adjustment to the oregano at the higher levels.