In this study, fruits from seed propagated walnut (Juglans regia L.) trees were collected two consecutive years in harvest seasons in Yozgat province in Turkey. Considering two years results, promising five genotypes were determined as cultivar candidate. In the promising genotypes, nut weight ranged from 12.55 (Y11) to 15.08 g (Y15), kernel weight ranged from 5.23 (Y11) to 7.34 g (Y15) and kernel ratio varied between 41.67 (Y11) to 50.84% (Y1), respectively. Linoleic acid was the only polyunsaturated fatty acids and oleic, palmitoleic and gondoic acids determined as major monounsaturated acids ranged from 30.36 to 48.43%, 0.05 to 0.14% and 0.22 to 0.29%, respectively. Propylparaben was the major phenolic acid among the determined phenolic acids in fruits of all five promising genotypes and Y16 had the highest amount of propylparaben (128.08 mg per kg) in its kernel. Malic and tartaric acid were the major organic acids in walnut kernels ranged from 47.88 to 78.51 mg per 100 g and 30.27 to 49.60 mg per 100 g, respectively. L-ascorbic acid was the another organic acids in walnut kernels ranged from 10.71 to 19.71 mg per 100 g. Citric acid was non-determined in kernels of Y1, Y14 and Y15 but determined at kernels of Y11 and Y16 as 4.51 and 7.55 mg per 100 g, respectively. It was determined that the oxalic, malonic, succinic, maleic and fumaric acid contents varied between 8.39-12.08 mg per 100 g, 6.02-9.19 mg per 100 g, 2.86-5.32 mg per 100 g, 0.26-3.00 mg per 100 g and 0.26-0.58 mg per 100 g, respectively.