The second case of human infection with Mesocestoides lineatus in Korea was reported. The patient, a farm worker, complained of abdominal pain and massive discharge of sesame-like proglottids in his stool for several months. Worms, recovered by chemotherapy with niclosamide, consisted of 32 strobilae. This may be the heaviest worm burden in human infection ever reported. The infected man habitually ate the raw viscera of chickens.