Direct examinations of blood and serologic tests were used to assess the intensity of the filarial endemicity in Gabon. Both methods revealed that the prevalence of filariasis with microfilaremia (Loa loa and Dipetalonema perstans) is presently very elevated. The areas that are more involved are the forest and the highest regions (Ogoue, Lolo, Ngounie). Women appeared to be less susceptible to loasis than men, but the prevalence rates were identical for D. perstans. Of the Gabonese population, 3 of 5 adults have filariasis (2 D. perstans and 1 L. loa). These infections represent a major public health problem. No lymphatic filariasis has been identified.