According to the Guinness Book,
The world's smallest dog living is Whitney,
(this photo IS NOT HER)
a Yorkshire terrier who measured 3 inches to the shoulder and
9.5 inches from nose to tail-tip on November 26, 2002.
Whitney is owned by Christopher and Patricia Sheridan of Essex, UK.
In 1945, allegedly, there was a Yorkie who was a mere 2 1/2" tall
and 3 - 3/4" long! The pup weighed 4 ounces!