During the period 1972-1974 10 patients suffering from pyogenic spondylitis have been treated at the Central Hospital of Middle Finland. Three of the patients had become acutely ill with septic fever and back pain. In the remaining cases the onset of the disease was insidious. Fever, weight loss and fatigue were the general symptoms. Percussion revealed local tenderness at the site of infection in all patients. Two patients showed neurological signs. The ESR was elevated in all cases and alkaline phosphatase was elevated in six patients. Blood culture was positive in those three patients who had become acutely ill. Narrowing of the intervertebral space was observed in all patients. Scanning with Tc99 was performed in nine patients, seven of whom were at an early stage of the disease; a significant uptake was recorded in five of these cases. The average interval between the onset of symptoms and the diagnosis was 3 months, range 1 to 5 months. The treatment consisted of bed rest and antibiotics. All the patients recovered and became symptom-free.