Lettuce is an important crop consumed fresh during winter and spring time. In the past 20 years, aphids have emerged as a major pest problem in lettuce fields of eastern Mediterranean region in Turkey. In this paper, we conducted survey studies to determine aphid species of lettuce and also monitored their population and flight activity during growing season of 2009-2010. Seven aphid species, Aphis gossypii Glover, Aulacorthum solani (Kaltenbach), Hyperomyzus lactucae (L.), Myzus (Nectarosiphon) persicae (Sulzer), Nasonovia ribisnigri (Mosley), Rhopalosiphum nymphaeae (L.) and Pemphigus bursarius (L.) (Hemiptera: Aphididae), were determined in the region. Nasonovia ribisnigri emerged as the most common among these aphid species. An increase in population was detected in the first plantation lettuce field in November (2009), but another peak was also observed in March (2010) in the second planting period of lettuce during the study which aimed to determine aphid population fluctuations in lettuce fields. In addition, there was no aphid detected during the third planting period of lettuce when milk formation (bitter) occurred and temperature increased. The twelve aphid species that were determined in total were collected by water pan trapping during the study to determine the flight activity of aphids, while six of them were also observed in fields. Hyperomyzus lactucae (41%), N. ribisnigri (16%), and M. (N.) persicae (24%) accounted for 81% of the individuals captured in traps. The flight activity patterns of N. ribisnigri in traps were quite similar to those observed in the field.