Surveys of the region's three major protected forest areas, the Maiko National Park, the lowland extension of the Kahuzi-Biega National Park, the Okapi Wildlife Reserve, and surrounding ungazetted areas have been undertaken. The authors present information on the impact of current human activity in the three protected areas and their adjacent hinterlands and provide population estimates and information on elephant Loxodonta africana, Grauer's gorilla Gorilla gorilla graueri, chimpanzee Pan troglodytes and okapi Okapia johnstoni both inside and outside protected areas in the region. All these species have large area requirements. Thus, trends in their populations are a sensitive indicator of the conservation status of the region. -from Authors