Porcine brucellosis is one of the most important zoonoses in this country. Currently, there is no control program for porcine brucellosis in Argentina and the epidemiological situation is still unknown. The purpose of our study was to detect anti-Brucella spp. antibodies in swine in the southwest of the Buenos Aires province and the east of the La Pampa province. Blood samples were obtained when animals were slaughtered. The presence of anti-brucella antibodies was studied by the buffered plate agglutination test (BPA), the tube agglutination test (SAT), the 2-mercaptoethanol (2-ME) agglutination test and indirect ELISA tests, using the cytosolic fraction from Brucella abortus S19 (CYT), and lipopolysaccharide (LPS)-free cytosolic proteins (CP). Out of a total of 325 samples analyzed, 17.8% reacted positively to BPA, 13.8% to SAT, 8.0% to 2-ME, 21.0% to ELISA-CYT and 10.0% to ELISA-CP. These results agree with the few data available in our country and suggest that brucellosis screening should be extended to other regions.