Research on fruit quality traits was carried out on the hazelnut ‘Cakildak’, ‘Fosa’, and ‘Tombul’ grown in Kocaali county of Sakarya province, Turkey, in 2009 and 2010. For this research, three orchards were defined and studied with three replicates for all cultivars. Each replicate was represented by three ocaks. The nut samples were harvested from a total of 27 ocaks either by picking directly from the branch or the ground, following a randomized block design based on cultivar or harvest treatment. For each replicate, nut weight and size, shell thickness, kernel weight and size, internal cavity size, kernel percent, the proportion of poorly filled nuts, shriveled kernels, blank nut ratio, good kernel ratio, pellicle removal ratio, and small nut ratio were determined. Further, pellicle removal and small nut proportions were also determined. As a result of this study, it can be said that quality traits were significant to picking method × cultivar interaction and better results were obtained picking by hand from ground. In general, the samples that were picked from the branch had thicker shells, more internal cavity space, a larger ratio of poorly filled nuts, and more shriveled kernels then nuts picked from the ground. In the case of the samples which were picked from ground, they had a greater nut weight, nut size, and better ratio of good kernel compared to those picked from branch. In addition, the heaviest nuts and kernels and the largest nuts and the lowest small nuts were determined in ‘Fosa’, ‘Cakildak’, ‘Tombul’, respectively.