This study was conducted to determine the optimum level of DL-methionine for finishing pigs fed 10% CP corn-soy diet fortified with 0.30% L-lysine and 0.09% L-threonine. One hundred and twenty finishing pigs (L × W × D: 56.6kg BW) were randomly allotted to 4 supplemental levels of DL-methionine treatments(0, 0.035, 0.07 and 0.105%) for 63 days per replicate. respectively. A metabolic trial was conducted with 12 pigs for 5 days after the feeding trial. Results obtained were summarized as follows; 1. There was significant difference(p$lt;.05) among treatments, the best value of daily weight gain and feed conversion were recorded with the 0.07% treatment. Daily feed intake were better in 0.035% treatment than the other treatments. 2. Although there was no significant differences among treatments, the highest values of crude protein digestibility, TDN and nitrogen retention were recorded with the 0.07% treatment. However, the methionine availability value(89.28%) of 0.07% treatment was significantly(p$lt;.05) higher than those of the other treatments. 3. The free S-containing amino acid level of plasma tended to increase as dietary level of methionine increased. However, the plasma urea-N level was the lowest in 0.07% treatment. 4. The total non-sulfar free essential amino acid level of plasma was lowest in 0.07% treatment and showed tendency to increase as the methionine level increased to 0.105%. It could be concluded that the optimum level of DL-methionine supplementation for finishing pigs fed 10% CP corn soy diet is 0.07%, resulting in 0.40% S-containing amino acids in the diet.