Two experiments were conducted to determine the effects of deletion of vitamin and trace mineral premixes on growth, feed efficiency, backfat thickness, hemoglobin content, muscle vitamin E content, and fecal, serum and muscle trace mineral contents in finishing pigs raised under two different housing conditions. In Exp. 1, three pens (or experimental units) of five pigs each (average weight ± s.e., 70 ± 0.5 kg) were assigned to a control diet (with vitamin and trace mineral premixes) or diets with 50 or 100% of the premixes deleted. Pigs were fed to market weight under sub-optimal housing conditions with sawdust-covered concrete floor and no electrical ventilation. In Exp. 2, three pens of four pigs each (average weight ± s.e., 56 ± 1.1 kg) were assigned to a control (with vitamin and trace mineral premixes), Diet-P (100% of the premixes deleted) or Diet-P+E (Diet-P plus 100 mg -tocopherol acetate/kg diet fed for the last 2 wk before slaughter). Pigs were fed to market weight under optimal housing conditions with 70%-slatted concrete floor, electrical ventilation and temperature control. No significant differences were found in average daily gain (ADG), average daily feed intake (ADFI), and gain/feed among treatments in both experiments, but in Exp. 2 done with younger pigs, ADG and ADFI tended to be higher in the control group than in pigs fed diet without premixes. Hemoglobin content, hematocrit and red blood cell count were not influenced by the deletion of premixes. Backfat thickness was not different among treatments. Fecal Mn (twofold) and Zn (threefold) contents were higher in the control than in pigs fed diets without the premixes. Serum trace mineral contents were not influenced by diets. -Tocopherol content in gluteus maxima was decreased (P 0.01) by deleting the dietary premixes, but increased to the level higher than the control by adding 100 mg -tocopheryl acetate/kg diet fed for the last 2 wk before slaughter. Results indicate that: 1) supplementary vitamins and trace minerals may not be necessary for optimum growth in finishing pigs, and 2) deletion of the dietary premixes reduces muscle vitamin E content, but the reduced content can be reversed by adding -tocopherol to diets fed for the last 2 wk before slaughter. The deletion may help to alleviate the environmental load of certain minerals from manure. (Key words : Pigs, Growth, Vitamins, Trace minerals, Vitamin E) Corresponding author : Kyu Il Kim, 1 Ara Dong (Phone : 82-64-754-3335; Fax : 82-64-725-2403; Email : kikim@cheju.ac.kr) Lee et al. ; Deletion of Vitamins and Trace Mineral Premixes in Pig Diets--544