This study was conducted to determine Thysanoptera species associated with nectarines and their damage on the fruits in Adana and Mersin provinces of Turkiye in 2005 and 2006. In the study, thrips species feed on nectarine and weed flowers and their population dynamics were found out. A total of 12 thrips species in the nectarine flowers were determined. These species were Frankliniella occidentalis (Pergande, 1895), Frankliniella intonsa (Trybom, 1895), Thrips tabaci Lindeman, 1889, Thrips meridionalis (Priesner, 1926), Thrips major Uzel, 1895, Thrips minutissimus Linnaeus, 1758, Thrips angusticeps Uzel, 1895, Isoneurothrips australis Bagnal, 1915, Melanthrips sp., Melanthrips pallidior Priesner, 1919, Tenothrips frici (Uzel, 1895) and Tenothrips discolor (Karny, 1907). Among the identified thrips species, F. occidentalis, T. tabaci, T. meridionalis, I. australis and T. major were more common. T. tabaci and F. occidentalis were more prevailing thrips species on the weeds sampled. Thrips adults infested the flowers at the beginning of the flowering period but the larval thrips appeared at the petal fall. Thrips feedings on ovary tissue caused brown blemishes-scars on fruit and feedings on mature fruit caused whitish skin patches called silvering. The orchard in Alifakili (Mersin) district having the highest number of adult and larval thrips in the flowers had the highest ratio of damaged fruits (60,1% and 73,8% in 2005 and 2006, respectively) at the harvest while Hadirli orchard with the lowest infestations of the total thrips in flowers had the lowest ratio of damaged fruits (17,7% and 15,6% in 2005 and 2006 respectively). According to the datas obtained from the study, a positive correlation between the total number of thrips in flowers and the ratio of damaged fruits due to thrips attacks may be mentioned but further research and statistical analysis are required to establish a correlation.