Organised sports are a popular form of physical activity, but unfortunately, participation can result in injury. Despite this, there have been surprisingly few studies that have reported the population rate of sports injury. Data from the 2005 New South Wales (NSW, Australia) Population Health Survey were analysed to describe self-reported injury experiences during participation in organised sports activities and the source of treatment for such injuries during a 12-month period in a population representative sample of adults aged 16+ years. At interview, 2414 respondents stated that they had participated in organised sport in the previous 12 months and just under one-third (30.9%) reported that they had been injured during this participation. Half of all injuries required formal treatment from a health or medical practitioner. Physiotherapists most commonly provided treatment for sports injury (26.6% of cases) followed by general practitioners (15.6%). Only 2.8% of all injured sports participants were admitted to hospital for their injury and a further 6.1% received treatment in an emergency department. This corresponds to at most only 8.9% of all treated sports injuries receiving treatment in a hospital setting. Population-based estimates of the rate and burden of sports injuries that rely solely on routine hospital data collections are likely to grossly underestimate the size of the problem, as very few cases are treated in a hospital setting.