Toxoplasma gondi, Leptospira spp., and Brucella abortus are all established parasitic and bacterial zoonoses that manifest themselves in several forms of human diseases. They have been associated with occupational exposures, particularly amongst workers associated with livestock farms. The primary objectives of this study were to determine the seroprevalence of T. gondii immunoglobulin M (IgM) immunoglobulins (serum antibodies), Leptospira IgM immunoglobulins, and B. abortus IgG immunoglobulins, suggestive of acute or chronic infections, in livestock/farm and abattoir workers in Trinidad, and to relate to risk factors. Blood samples were collected from 394 consenting livestock/farm workers and 99 abattoir workers across the island of Trinidad. Serological status was determined by enzyme immunoassay (EIA) for T. gondii IgM, enzyme-linked immunosorbent assay (ELISA) for Leptospira IgM immunoglobulins, and buffered plate agglutination test (BPAT) and competitive ELISA for B. abortus IgG immunoglobulins. Of 394 apparently healthy livestock/farm workers sampled, 150 (38.1%) were seropositive for T. gondii IgM immunoglobulins, compared with 44 (44.4%) of 99 abattoir workers (p > .05; χ(2) test). Five (1.3%) of 371 and 1 (1.0%) of 99 livestock/farm and abattoir workers respectively were positive for Leptospira IgM immunoglobulins. All samples from livestock/farm workers and abattoir workers were negative for B. abortus immunoglobulins. None of the risk factors investigated was statistically significantly (p > .05; χ(2) test) associated with T. gondii and Leptospira spp. infections.