Disclosed herein are a microorganism strain capable of producing the L-methionine precursor O-acetyl homoserine in high yield and a method of producing O-acetyl homoserine using the same. The microorganism strain is a strain of Escherichia sp. in which an acetyl-CoA synthase gene (acs) and/or a pantothenate kinase gene (coA) encoding a pantothenate kinase gene refractory to feedback inhibition by CoA is introduced and expressed.