Last name Задоиан (Задоиан 
, Zadoyan 
) , worldwide, is a rare cognomen. The surname Задоиан is characteristic of Armenia, where it is quite a rare surname, New Zealand, where it is a very rare surname, and Russia. Measured by absolute frequency, it is commonest in Armenia, Russia, and the United States.
| VARIANT | COUNTRY |
|---|---|
| Задоиан | Russia |
| Zadoyan | Germany, Armenia, Russia, United States, Canada |