This study presents the concentration of mercury in feathers of 40 owls (five species) in five regions of Iran. Results showed that mercury concentration in Tawny owl’s feathers (Strix aluco) were significantly higher than in the Little owl (Athena noctua), Eagle owl (Bub bubo), Long-eared owl (Asio otous) and Short-eared owl (Asio flammeus). Also, mercury concentrations in owl feathers collected from the north of Iran were significantly higher than others regions. Furthermore, mercury concentrations in owl feathers obtained in this study were higher than other regions in the world except for Sweden. This study demonstrates that mercury concentrations in Iranian owls, with the exception of the Tawny owl, are below toxic concentration (5 mg kg-1). In addition, location was a contributing factor in the mercury concentration in Iranian owl’s feathers.