The clinical data from 19 patients with brucellar spondylitis and 15 with tuberculous spondylitis were compared. The former disease affects males whose occupations expose them to Brucella. The lumbar spine is usually involved and there are other symptoms of brucellosis. Tuberculous spondylitis is not usually accompanied by general symptoms. The dorsal spine is more frequently affected and may exhibit vertebral collapse and paraspinal abscesses. These differences permit a presumptive aetiological diagnosis, but the definitive diagnosis depends upon bacteriological tests.