It has been noted since the earliest European contact that Polynesian body shape and size differ from those of Europeans. The muscular build of Polynesians, such as Tongans, raises questions as to the accuracy of simple anthropometric indicators, validated for use in European populations, in Polynesians. Body mass index (BMI), total body fat and an abdominal fat window were measured in a sample of Tongan [28 male (M), 28 female (F)] and Australian Caucasian adults (39 M, 46 F), with standard anthropometric and densitometric methods. Tongan males (BMI, 32.8+/-4.6 kg/m(2)) were heavier than Australian males (BMI, 27.1+/-3.7 kg/m(2)); but differences in total body percent fat (28.9+/-8.3 vs. 25.9+/-8.1, p=0.15), abdominal fat (1.84+/-0.69 vs. 1.55+/-0.60 kg, p=0.07) and abdominal percent fat (30.3+/-8.6 vs. 28.5+/-8.3, p=0.40) were non-significant. Tongan females (BMI, 34.3+/-5.5 kg/m(2)) were also heavier than their Australian counterparts (BMI, 26.2+/-6.3 kg/m(2)); with the difference in total body percent fat (41.9+/-5.2 vs. 38.7+/-8.9, p=0.05) and abdominal percent fat (39.3+/-4.8 vs. 33.6+/-8.9, p=0.001) less than expected, given the difference in BMI. This study demonstrates significant body composition variations between Tongans and Caucasians.