The study was conducted to determine the extent of illegal harvesting of Pterocarpus chrysothrix (Mukula) tree species in Nyanganje Forest Reserve of Isoka District in Muchinga Province. Data on the extent of illegal harvesting of Pterocarpus chrysothrix (Mukula) species was collected by socio-economic and ecological surveys. Ten (10) Villages were selected at random based on their closeness to the forest resources within these villages. A sample size of 150 individuals was targeted using purpose sampling and questionnaires were administered using semi-structured interviews. The survey also targeted key informants in the area (i.e. village environmental committee and village leaders). The findings from the study indicate that the area has a total standing volume of 29,035.6 m3. This means that the area has great potential in timber production provided sustainable timber harvesting is practiced. The findings indicate that the mean annual quantity of wood harvested illegally was estimated to be 6.2 m3 per ha. This means that the tree species may be depleted if sustainable measures are not put in place to safeguard the tree species.