The authors report 136 cases of spondylodiscitis due to ordinary organisms seen between 1980 and 1989 and note the increasing incidence of iatrogenic forms which during the past three years accounted for 50 per cent of cases. 60 per cent of these cases of iatrogenic spondylodiscitis complicated a medical of surgical procedure involving the spine (form by direct inoculation). In 40 per cent of cases, the organism came from a site of infection located at a distance (from by blood-borne spread). The clinical picture in cases of primary spondylodiscitis and of iatrogenic disease by blood-borne spread is essentially similar. That of iatrogenic forms by direct inoculation is different: most often young subjects, virtually exclusive involvement of the lumbar spine, fever and inflammatory syndrome less common. Escherichia coli and Staphylococcus aureus were the organisms most often responsible for primary spondylodiscitis (23 and 21.7 per cent of case respectively). Streptococci were in third position only (15.6 per cent of cases). Staphylococcus aureus remained predominant in iatrogenic spondylodiscitis (34 per cent of cases), while Escherichia coli and streptococci were significantly rarer than in primary forms and there was the appearance of Pseudomonas aeruginosa and Staphylococcus albus. No organism was found in 23 per cent of cases of primary spondylodiscitis. This figure reached 44% of iatrogenic forms by direct inoculation. Because of their increasing incidence, these cases of apparently aseptic spondylodiscitis, frequently complicating a procedure involving the spine, are modifying the picture of infectious spondylodiscitis. No doubt worthy of separate identification, they raise the problem of the significance of the concept of aseptic spondylodiscitis.