Although equestrian injury studies to date have provided useful information for injury prevention, these studies have not been detailed enough or inclusive enough, to identify and characterise all sub-populations that may be at risk. One study has reported injury rates for the population-at-risk. The present study was carried out to determine, more precisely, who is injured in horse-related activities in New Zealand, what sorts of injuries they sustain, the circumstances of injury and the cost of treatment. A novel search of linked hospital discharge and compensation claim data for 2002 and 2003 was carried out. Of 716 newly hospitalised cases, 29% were in the 5-19-year and 28% in the 35-49-year age groups. Incidence rates for regular riders peaked at 13-15 years (900/100000) and 50+ years (880/100000). Where the 'place of occurrence' was specified only 12% of cases sustained injury in a 'sports and athletics area'. This new study has highlighted injuries occurring in farm and other 'open' locations such as mountains and forest, injuries to older riders and injuries to bystanders/handlers during non-organised recreational activity. Attention was drawn to the high in-patient cost of hospitalised injuries in persons >40 years and the need for injury information relating to specific riding activities. Current equestrian injury prevention tends to target young females and organised riding; in focusing on these, other significant population groups and injury mechanisms may be overlooked and opportunities for injury prevention missed.