A study on Javan rhinoceros (Rhinoceros sondaicus) in Ujung Kulon National Park, Banten was done to monitor the levels of stress in their natural habitat. The study found that glucocorticoid hormone metabolite 3α,11β-dihydroxy-CM from feces was suitable for indicating the levels of stress in Javan rhino. The assessment was done to study stress variations among the three rhinoceros that had different levels of feed intake, as well as to study variations of stress levels in dry and rainy seasons. The result from this study showed that there were fluctuations of 3α,11β-dihydroxy-CM levels in two of the three rhinoceros. These fluctuations reflect the levels of stress associated with energy intake deficit (energy intake per body weight) and water deficit. This research shows that the deficit in energy intake per body weight, and water limitation are among the biggest sources of stress for rhino population. Stress originating from deficit of nutrients from food plan can be overcome by enriching the habitat of the Javan rhinoceros with high nutrient food plants such as stink vine (Paederiascandens), blackboard tree (Alstoniascholaris), and wild ginger (Costusspeciosus). Stress originating from water deficit can be mitigated by opening tracks and ensuring access to permanent year-round water sources.