Infection rate of imported monkeys, under this study, with intestinal protozoa is higher than the infection rate with intestinal nematodes. Mostly encountered protozoa were E. coli, E. nana, E. histolytica and I. butschlii. Formalin-Ether concentration method yielded higher % positive for E. histolytica than the culture method using Tanabe-Chiba medium, but the results obtained from these 2 methods correlate perfectly well with each other. Efficacy of thiabendazole against intestinal nematodes such as Strongyloides, Trichuris, Physaloptera, Oesophagostomum and Capillaria was very satisfactory.