Samandag Beach in Turkey is one of the three most important nesting beaches in the eastern Mediterranean for the critically-endangered green turtle (Chelonia mydas), and is also a nesting area for the loggerhead turtle (Caretta caretta). In this study, the nesting characteristics of green and loggerhead turtles on Samandag beach were determined during the nesting season from 2001 to 2005. During the five-year monitoring, the mean green and loggerhead turtle nest numbers were 121 (range = 16-325) and 11 (range = 7-20), respectively. The mean ratio of non-nesting emergence to nesting emergence (1.6) was lower than the ratio reported in previous studies. The green-turtle nest density on Samandag beach (14 km), and Seyhhizir beach (4.1 km), was 9.3 (range = 1.1-23.2) nests/km and 23.5 nest/km (range = 3.4-64.4), respectively. Loggerhead turtle emergence was randomly distributed, the emergence of green turtles (94.1%), however, was concentrated approx. 3 km north and 3 km south of the Asi River. The emergence of both species took place mainly in July. The average hatching success of green and loggerhead turtles was 70.38% and 71.8%, respectively, with minimum and maximum incubation durations of 43-67 and 44-61 days, respectively.