Serum immunoglobulin G, A, M, D and E levels were determined in the forest-dwelling Orang Asli of age group 8 to 64 years. The levels are higher than observed for urban Malaysians and comparable to levels reported for populations residing in the tropics. There was no significant difference in serum levels of all the immunoglobulins studied in both sexes. The elevated serum immunoglobulins levels are discussed in terms of the nature of the immune defence developed in the Orang Asli to contend with the many parasites prevalent in their environment.