We investigated the residues of β-agonist (zilpaterol, ractopamine and clenbuterol) using LC-MS/MS in raw meat in Seoul. The recoveries ranged between 76.7∼89.9% in beef respectively. The limits of detection were 0.01∼0.09 μg/kg and the limits of quantification were 0.03∼0.28 μg/kg respectively. Residues of β-agonist drugs which exceeded maximum residue limits (MRL) were not exceed in any of the 267 samples.