The present invention relates to mutant microorganisms having high ability to produce putrescine in which genes involved in the putrescine degradation or utilization pathway of microorganisms having a putrescine-producing metabolic pathway are inactivated or deleted; and a method for producing putrescine in high yield by culturing the mutant microorganisms under anaerobic conditions. The mutant microorganisms having high ability to produce putrescine are useful for producing a high yield of putrescine which is used in a wide range of industrial applications.