Historically the Ituri forest of northeastern Zaire has been exploited only by small bands of pygmy hunter-gatherers and isolated groups of shifting cultivators. Enforced village resettlement in the 1940s and increasing immigration from the densely populated southeastern highlands has caused a considerable expansion of clearing for horticulture in some regions of the forest. As a consequence, large, coterminous zones of Musanga cecropioides-dominated secondary forest now border the roads. To assess the impact of forest clearing for subsistence farming on the diversity and abundance of terrestrial mammals, tracks and pellet groups were counted over a one year period within three five-ha uncut climax forest sites and three five-ha post-agricultural secondary forest sites. Relative diversity and abundance of terrestrial mammals were comparable to other central African rain forests. Of 19 species identified, only Okapi, yellow-backed duikers, and leopards were less abundant in post-agricultural forest. Smaller duikers seem unaffected by forest clearing for subsistence farming, even though they are an important food source for humans. Habitat loss, or hunting pressure, has reduced the abundance of larger ungulates near villages.