According to Vetstreet, Chihuahuas live 12 to 20 years. Healthy Chihuahuas have one of the longest life spans of any breed of dogs. They are also the smallest breed and the only natural toy-sized breed.
While the Chihuahua can enjoy a long life, there are many health problems that tend to plague these dogs. Like many small dogs, Chihuahuas can develop tracheal collapse, which causes a severe obstruction to the airway. Many Chihuahuas have a molera, an open soft spot on the skull that never completely closes, which may lead to head injuries, seizures and death. Some Chihuahuas have a portosystemic shunt, a birth defect that causes the blood to be diverted away from the liver and leads to a deadly buildup of toxins.