Understanding deer habitat use is important in predictive management of increasing deer populations and in assessing the potential for inter-specific competition, particularly between native and introduced species. Habitat usage by roe deer and introduced Chinese muntjac was studied in a 1200 ha study area within Thetford Forest, a commercially managed coniferous forest in Eastern England. Habitat use was related to forest growth stage and vegetation composition by pellet-group clearance transects conducted every 2 months from March 2000 to March 2001. Higher densities of roe deer were found in young plantations, while muntjac numbers were lower in open restocks and grassy areas and higher in older stands and areas with greater cover of bramble Rubus fruticosa agg. Overall, muntjac showed greater habitat selectivity than roe deer. The overlap between the two species in use of individual stands (single, even-aged management compartments) was significantly lower than overlap in use of growth stages (consisting of many individual stands), suggesting ecological partitioning at finer spatial scales. However, overlap in habitat use as measured by Pianka’s index remained substantial at both scales (mean 0.40±0.16 S.D. for stands and 0.55±0.11 for growth stages). Habitat overlap was greatest in winter when both species aggregate on bramble. There is, therefore, potential for exploitation competition in the event of food scarcity.