Prevalence of brucella-specific antibodies was measured in 597 persons in high-risk occupations living in 10 regions of Lebanon using the standard agglutination test (SAT), anti-human globulin (Coombs') test (AHGT) and enzyme-linked immunosorbent assay (ELISA) for measuring immunoglobulin G (IgG), IgM and IgA. The study population consisted of butchers (54%), farmers (35%), laboratory technicians (8%), abbatoir workers (2%) and veterinarians (1%), with 82% males and 18% females. The overall seroprevalence based on SAT and AHGT titres of > or = 80 was 1.7% and 15%, respectively, but seroprevalence varied by region from 0-5% in SAT and from 3.4-34% for AHGT. The overall seroprevalence based on ELISA IgG (OD > or = 0.6), IgM (OD > or = 0.6) and IgA (OD > or = 0.3) was 57, 61 and 26%, respectively. The highest seroprevalence was noted in Biqaa (34%), Kisrwan (24%), Shouf (21%), Sidon (16%) and Aley (12%) regions. Nineteen percent of those surveyed reported symptoms that could be associated with brucellosis. We conclude that exposure to brucellosis is high among persons in high-risk occupations from all surveyed regions in Lebanon. Such findings should be used to design control measures especially now that the 17 years of civil strife is over.