An investigation on the digenetic trematodes parasitizing free range reared guinea fowls was conducted in the state of Rio de Janeiro, Brazil, based on clinical examination, necropsies and histopathologica l findings in 36 guinea fowls. Parasites, prevalence and intensity of infection were, respectively: Paratanaisia bragai, 61.1% and 31 (in each kidney); Athesmia heterolecithodes, 8.3% and 38; Conspicuum conspicuum, 2.8% and 1. A. heterolecithodes was highly pathogenic to guinea fowls, causing severe hepatic lesions. However, C. conspicuum and P. bragai were less pathogenic in the considered intensities of infection. This is the first time that these parasite species have been reported in Brazilian guinea fowls.