The EPIBAC network is a network of hospital microbiology laboratories whose objective is to monitor certain community-acquired invasive infections. EPIBAC aims to estimate the incidence of these infections, track their trends over time, and describe certain epidemiological characteristics (age, sex) of patients affected by these infections. 259 hospital laboratories (63% of all hospital laboratories) participated in EPIBAC in 1997. The incidence of invasive infections is relatively stable, with the exception of H. influenzae infections, which have continued to decline since 1991; S. pneumoniae infections, which have been increasing steadily by more than 4% per year since 1994; and a slight increase in Group B streptococcal infections from 1996 to 1997.