Chihuahua, 15-20 years
Though Chihuahuas aren’t the best dogs for homes with small children, and they do have their fair share of health problems (too much Taco Bell perhaps?), they also tend to have a longer life span than many other breeds.
They typically only weigh between 5-7 pounds (the smallest dog breed on the planet actually) and live, on average, between 15 and 20 years.