Infectious diseases can be either from primates to humans or from humans to primates. There have many ways of infection such as through air, food, water, and physical contact. The behavior of monkeys who like to dig up the trash, throw rubbish everywhere can enhance risk of infection. The intestinal parasite also can be transmitted through faeces and this becomes even worse when the monkeys often leave droppings and urine after entering the premises and human housing. In addition, the infection can also be transmitted through physical contacts such as fondling, scratches, and bites. Therefore, the survey of intestinal parasites found in long-tailed macaque using flotation method is important to recognize the type of parasites in the intestinal. The study was conducted at Kuala Selangor Nature Park (KSNP). These locations are the main route for the long-tailed macaques and humans. The result found that there are five parasites which were Ascaris lumbricoides, Strongyloides sp., Oesophagustomum sp, Ancylostoma sp., and Entamoeba sp. This study provides baseline data for intestinal parasites of long-tailed macaque in peninsular Malaysia. However, this research is still early and too broad and should be concerned with other factors such as life cycled, immune systems strength and moisture level that might influence infection. Recommendations can be given to reduce infection is by enforcing the payment of fines and penalties to those who sell and feed the monkeys. Apart from that, the responsible parties such the Department of Wildlife and National Parks (DWNP) and Malaysia Nature Society (MNS) should initiate an awareness program for the local people nearby and for the tourists to reduce direct contact between humans and monkeys. The parties of the water resources management and sanitation such as Selangor Water Supply Company (SYABAS) and Kuala Selangor District Council (MDKS) also should play an effective role in curbing transmission of infections.