To describe bacteriologic epidemiology of bone and joint infections, a total of 52 osteomyelitis, 52 arthritis and 20 osteoarthritis of children aged one month to 15 years during a one-year period (2001) were included in a retrospective unicentric review. The mean age was 3,9 +/-3,6 years. Fever and pain were the most common clinical symptoms. The site of infection was single in 95%, involving lower extremities in 80%. Bone scintigraphy was abnormal in 71% of osteomyelitis. Positive cultures was obtained in 29% of all cases (blood cultures: 20%, aspiration cultures: 29%), but in 42% of cases which have both blood and aspiration cultures. Thirty-six bacteria were identified: 19 Staphylococcus (14 aureus), ten Streptococcus (four pneumoniae), three Salmonella, three Kingella kingae, one Moraxella. All the isolates were susceptible to the empiric antibiotic therapy. Outcome was good in 100% of osteomyelitis and in 96% of arthritis.