This study investigates the gut microbiota of captive deer (Rusa timorensis) at Gunung Reng, Jeli, Kelantan, with a focus on identifying and comparing the microbial communities present in captive and wild deer populations. Rusa timorensis, a species native to the Indonesian archipelago, has been introduced to various regions, including Malaysia, where it is valued for its adaptability and resistance to disease. The research aims to classify gut microorganisms using simple staining techniques and compare microbial classes via secondary data. Captive conditions, including diet and habitat, significantly influence gut microbiota, impacting health and adaptability. This study collected faecal samples from deer at Gunung Reng and conducted microbial analysis using various agar media and microscopy techniques. Results indicated distinct differences in microbial composition between male and female deer, with notable implications for health management and conservation efforts. Understanding gut microbiota dynamics in captivity can inform strategies to enhance animal welfare and ensure the sustainable management of captive populations.