Three patients requiring abdominal exploration because of severe abdominal pain were found to have infection of the intervertebral disk. Clues to diagnosis of intervertebral infection are: backache, which is spasmodic and referred to the lower abdominal quadrants; an elevated erythrocyte sedimentation rate; narrowing of the involved intervertebral disk; erosion of the vertebral end plates; and bridging of the disk space by new bone formation. The presence of leukocytosis and fever is not required for diagnosis. Immobilization of the spinal column is the most effective treatment. Spontaneous fusion of the involved segments of the spinal column is the rule and antibiotics should be used only when the infection has extended from the interspace to surrounding soft tissues.