Habitat degradation and fragmentation are eating deep into conservation areas and this is a serious threat to species diversity and abundance. Species like the antelopes have a sedentary and docile nature which makes them highly vulnerable to habitat degradation or human intrusion. The effect becomes complex as the remaining flora and fauna communities can be significantly impacted by changes in ecosystem structure and function. Population density, diversity and abundance of fauna species will either increase or decrease over time depending on the quality of the environment/habitat and the level of human interference or disturbance. Hence an updated checklist of species diversity and abundance is necessary to enable management and other stakeholders make pragmatic plans and policy towards sustainable species conservation. With the aid of a Global Positioning System (GPS), a 5 km transect was established per site and censured for Antelope species using the King Census method of enumeration. Descriptive statistics and ANOVA was used to analyze the data. Seven (7) species of Antelopes were recorded. Kobs (Kobus kob) were the most abundant (2019), while Reedbuck (Redunca redunca) was the least abundant with twenty-five (25) individuals. Kob is the most observed species in Oli Complex with 24.13%, ranking about 50% of kob in proportion. This was followed by roan antelope (Hippotragus equinus), and Red Flanked duiker, 4.02% and 3.63% respectively. Kobs had the highest density of 40.38 per square km followed by roan antelope (3.32) and RF duiker (2.36). Relative density followed a similar trend. The least encounter rate was observed in Sylvicapra grimmia (0.02) and increse further to Hippotragus equinus (0.4), Redunca redunca (0.06) and Alcelaphus buselaphus (0.09) respectively. It was low amongst Tragelaphus scriptus (0.2), and moderate, while it was very high amongst the kobs (5.0). The rate of encountering an antelope in the park is very high at a rate of 6.2 animals per kilometer. Species of antelopes are almost not found in other ranges due to anthropogenic activities around the park. These activities are fast entering into the core area of the park. Hence management should take effective measure to curb this fast-rising problem.