Diversity of the genus Dolichopus Latreille in three different habitats of East Azerbaijan Province, with new records for Iran.-The present study is a survey of species diversity of the genus Dolichopus in East Azerbaijan province, Iran. The species were collected using a standard entomological net from three habitats (forest, grassland and wetland areas) in northwest Iran in 2013. Based on the data collected, the forest area with the highest diversity indices (H' = 2.53, 14 species, and H' = 2.19, 10 species, in Chichakli and Keleybar regions respectively) had the most diverse and abundant species, followed by grassland and wetland areas. The dominant species in the study areas were Dolichopus longitarsis and D. simplex. Besides, three species (D. siculus, D. kiritshenkoi and D. plumipes) were recorded from Iran for the first time. Diagnostic characters and geographical distribution of the species occurring in the studied areas with supplementary figures are provided.