Abstract: The impact of Dubri Oil Company operations on the macrobenthic invertebrate fauna of Osse River, Edo State (Nigeria) was investigated between July 2000 and June 2002. Fifty-seven taxa which were well represented in the five stations were encountered. Ephemeroptera accounted for 26.30%, Decapoda (21.53%), Diptera (17.04%), Annelida (11.31%), Odonata (6.56%), Nematoda (1.45%), Coleoptera (0.75%) and Hemiptera (0.28%) of the total number of organisms collected from the study stations. The family Naididae (Annelida), Alpheidae (Decapoda), Chironomidae (Diptera), Baetidae (Ephemeroptera) and Libellulidae (Odonata) were the most widespread. The overall abundance of the macrobenthic invertebrate fauna was significantly different (p<0.05) among the study stations. A posteriori Duncan Multiple Range (DMR) test showed that the abundance was significantly higher (p<0.05) in stations 1, 2 and 5 than the other stations (3 and 4) which were not significantly different (p>0.05) from each other. The diversity indices revealed that taxa richness was highest in station 2 and lowest in station 5, while Shanon Wiener and Evenness indices were higher in stations 1, 2 and 4 than those of other stations. The temporal dynamics showed higher macrobenthic invertebrate fauna abundance during the dry season months than the rainy season. The impact of crude oil exploration on macrobenthic invertebrate fauna is reported.