A survey of workers and families resident in an oil palm estate in Malaysia revealed high incidence of parasitic infections. The commonest parasites are T. trichiura (56%), A. lumbricoides (52%), hookworm (28%), Entamoeba coli (11.3%) and Giardia lamblia (11.3%). Mixed infections by two or more parasites was seen in 46% of the subjects. Anaemia was present in 70% of children with hookworm infection. Eosinophilia was observed in 69% of subjects. One each of Hymenolepis nana and Hymenolepis diminuta infection was detected. This is the first report of Hymenolepis diminuta infection in man in Malaysia.