Causes of death and age at death of 2928 dogs are reported from a questionnaire study among members of the Danish Kennel Club (DKC) in 1997. The dogs represented 20 breeds, 15 breed-groups and a group of mixed-breed dogs. The median age at death for all dogs in the study was 10.0 years. Mixed-breed dogs had a higher median age at death (11.0 years) than the entire population, but breeds like Shetland Sheepdog, Poodle and Dachshund exceeded this age (12 years). The Bernese Mountaindog, the group of Molossian types and the Sighthounds had the shortest life span with a median age at death of 7.0 years. Old age was the most frequent reported cause of death (20.8%) followed by cancer (14.5%), behavioural problems (6.4%) accidents (6.1%), hip dysplasia (4.6%), heart diseases (4.6%) and spinal diseases (3.9%). Breed-specific proportional mortalities with 95% confidence limits are given for the six most prevalent specific causes of death.