A genetically modified microorganism that can produce 3-hydroxyadipic acid and/or -hydromuconic acid with a high yield; and a method of producing 3-hydroxyadipic acid and/or -hydromuconic acid using the genetically modified microorganism, are disclosed. The genetically modified microorganism has an ability to produce 3-hydroxyadipic acid and/or -hydromuconic acid, and has an enhanced enzymatic activity to catalyze a reaction to reduce 3-oxoadipyl-CoA to 3-hydroxyadipyl-CoA, wherein, in the genetically modified microorganism, a dicarboxylic acid excretion carrier function is deleted or decreased.