The NSW Schools Physical Activity and Nutrition Survey (SPANS 2004) (N=5407) was a representative population survey, conducted February–May 2004, among New South Wales (Australia) school students aged 4 y–16 y. Physical activity, fitness, fundamental movement skill proficiency and food habits are all related to overweight and obesity and were a focus of this study. The last population-based survey in NSW was conducted in 1997 and use of the same measurement instruments (with the exception of food habits) allowed examination of secular trends. Overweight and obese children are at risk for a number of serious, long-term health problems, and a sub-sample (n=500) of urban dwelling Year 10 students (mean age 15.4 years) gave a fasting blood sample which was analysed for the presence of risk factors for the metabolic syndrome. This paper describes the methods of the NSW Schools Physical Activity and Nutrition Survey 2004 (SPANS 2004).