The proboscis monkey or long-nosed monkey is diurnal and arboreal. This species is endemic to Borneo Island inhabit mangrove forest and swampland. Daily behavioral activities of the proboscis monkey kept in the Bekantan Rescue Center, Sahabat Bekantan Indonesia Foundation was interesting to be observed. A couple of adult proboscis monkey, which was approximately 10 years old for each individu, was utilized in the current study. Observation on daily behavioral activities included locomotion, eating, antagonistic, playing, grooming, and rest-activity. Proboscis monkey spent their daily time for resting, locomotion, grooming, eating, antagonistic, and playing with each percentage were 42.50%; 26.04%; 17.15%; 9.29%; 0.86%; and 0.13%, consecutively. Locomotion activities consisted of walk, jump, moving seat, swing, and cage-shaking. Grooming by removing pieces of dirt, dried skin, and insects from the hair were done individually and more frequently in female than male. Eating activities were 3 times a day, morning, noon, and afternoon with the duration of 5-15 minutes. An antagonistic expression such as opening wide-mouth, vocalization, and cage-shaking was frequently observed in the male shown when the unknown person was present. Playing activity was the lowest percentage activity observed. This activity is less frequently observed in the adult period. Rest activity consisted of night sleep and day sleep. Night sleep was observed from 09.00 P.M to 6.00 A.M, and day sleep was observed after eating time in the morning and noon. Daily behavioral activities of the proboscis monkey in the Bekantan Rescue Center tend to be done routinely and regularly.