Dog bites in humans are a complex problem embracing public health and animal welfare. To prevent dog bites it is necessary to have comprehensive epidemiological data that allow the identification of associated risk patterns. This study was aimed at investigating the problem posed by dog bites in Spain. The epidemiology of medically attended dog bite-related incidents reported in Aragón was analysed from 1995 to 2004. Bite incidents were mostly associated with: (1) low-population areas (71.3/100,000 inhabitants); (2) males and children, particularly those aged 5-9; (3) single injuries directed to the head and neck area in children and to the extremities in adults; (4) young, male, medium to large, owned dogs that were known to the victim; (5) summer months, and (6) specific circumstances such as human interference with knocked down and fighting dogs. In the light of these risk patterns, a wide range of specific preventive measures could be proposed.