A survey of helminth parasites was carried out on 198 dogs living in almost complete liberty in villages in the northeast of Gabon. Faeces and blood samples were collected and analysed. Dirofilaria immitis antigen was detected in 13.6% of dogs using the SNAP 3Dx test, a commercially available enzyme-linked immunosorbent assay (ELISA). Faecal examination revealed that 91.4% of dogs were infected by intestinal helminths. Ascarids were found in 58.5% of the samples. Trichuris vulpis was observed in 49.5% of cases, and Uncinaria spp. and Ancylostoma spp. in 34.8%, Spirocerca lupi in 25.3% and Capillaria spp. in 10.6%. Cestode embryophores were found in 8.6% of the samples.