The purpose of this study was to compare the sensitivity and specificity of an ELISA to detect Fasciola gigantica antigens in bovine faeces (coproantigens), with faecal egg counting and with an ELISA for detecting anti-F. gigantica antibodies in serum. Monoclonal antibodies to cathepsin L were generated and used to capture this antigen in faeces of infected cattle. Blood, faeces and livers were collected from 150 cattle at an abattoir in Jakarta, Indonesia for anti-Fasciola antibodies, for coproantigen detection and F. gigantica egg and worm counts. Fluke recovery varied from 1 to 426 with a mean of 32 flukes per animal. The results showed that the sensitivity and specificity of coproantigen detecting ELISA (95 and 91 , respectively) was better than the anti-F. gigantica antibody ELISA (91 and 88 , respectively) and to faecal egg counting (87 and 100 , respectively). The coproantigen ELISA was able to detect 100 of cattle with >15 flukes. A survey of 305 cattle in central Java over a 10 month period validated this test in the field demonstrating a high incidence of fasciolosis and establishing the test as a useful diagnostic method to determine patent F. gigantica infections in cattle.