The Health and Lifestyles Survey (HLS) is a biennial monitor of the health behaviour and attitudes of New Zealand adults aged 15 years and over, and parents and caregivers of 5 to16-year-olds, first carried out in 2008. The HLS is managed by HPA and collects information relating to HPA’s programme areas of alcohol, tobacco control, sun safety, minimising gambling harm, nutrition and physical activity, mental health and immunisation. This methodology report details the procedures and protocols followed to ensure the HLS produces high quality, robust data.