Qaen (, also Romanized as Ghayen, Qayen or Ghaen) is a city in and the capital of Qaen County, in South Khorasan Province, Iran. Qaen is also called the City of Saffron. Saffron from Qaen is prized for its unique aroma and strong colour. The population at the 2006 census, was 32,474 in 8,492 families.
Qaen is a place of great antiquity and complex history. The present city, which lies in a broad valley, was founded in the 15th century on the site of an ancient city. Later, the Uzbeks (a Turkic people) took possession of the city and held it until Shah Abbas I (1588-1629) expelled them. In the 18th century, Qaen fell under the control of Pashtuns which is why some of locals, though they speak Persian, still claim descent from Pashtuns (rather than Persians).
A mud wall surrounds the modern town. More affluent residential areas lie outside the wall. The city is a trading center, but it also has industries that produce felt and carpets. The surrounding area consists of hill ranges of 9,000 feet (2,750 m) running northwest-southeast and sinking to the Sistan depression in the south. The area is the main source of saffron in Iran, but it also produces grain, vegetables, and wood.
There are several ancient places around the town, such as the Tomb of Bozorgmehr Qaini, 5 km to the south.
At least 2,400 people in Qaen and the surrounding region were killed in the Ardakul earthquake on May 10, 1997.