Few studies are available on the population dynamics of medium and large mammals in gallery forests of the Sudan and Sahel regions of West Africa. Line-transect studies of the abundance (estimated by KIA) of nine species of ungulates and three species of primates were carried out between 2004 and 2013 in the Comoé-Leraba protected area of Burkina Faso, West Africa. No peer-reviewed study of population sizes of mammals in this protected area has been published, making the data presented of special relevance. Population size trends varied significantly across years in both primates and ungulates, with some species (Papio anubis, Phacochoerus africanus, Alcelaphus busephalus and Tragelaphus scriptus) decreasing consistently. Significant relationships were observed between poaching intensity and population oscillations in Erythrocebus patas, Kobus ellipsiprymnus, Kobus kob, Ourebia ourebi and Cephalophus rufilatus.