Primates are very selective in choosing suitable habitat. Proboscis monkey (Nasalis larvatus) is classified into family Colobinae and comonly eaten leaves. Feeding activity and food plant species of proboscis monkey at Bakut Island are a source of information for the rehabilitation programs. The method used was the focal animal sampling. Samples were observed in male and female adult individuals in the group of Alfa. The results showed that the feeding activity of proboscis monkey had regularity pattern in three periods; those were morning, daytime, and afternoon. Food plants identified were 9 species. Keywords: feeding activity, food, proboscis monkey