One of the aims of this study was to determine the effect of different boron sources on boron nutrition and growth of sunflower plant. Also it was aimed to examine the sunflower response to the over leaf boron concentrations. For this, 7 boron sources; Anhydrate borax (Na2B4O7), Boric acid (H3BO3), Etibor-48 (Powder; Borax pentahydrate, Na2B4O7. 5 H2O), Boron oxide (B2O3), Etidot-67 (Na2B8O13.4H(2)O), Borax (Na2B4O7.10H(2)O) and Etibor-48 (Granule; Borax pentahydrate, Na2B4O7.5H(2)O) were applied to 4 kg soil containing pots at the rates of: 0 (control), 5, 10 and 20 mg B kg(-1). Plants were grown under greenhouse condition until the flower bud period, and then plants were harvested and analyzed for nutrients. According to the results, leaf B concentration of sunflower increased up to 718 mg. kg(-1) with the boron applications. All boron sources increased the leaf boron concentration and the means were recorded as 105, 170, 250 and 483 mg. kg(-1) respectively. Sunflower growth and mineral nutrition were not affected negatively by the over leaf B concentrations.