Öz The present study was conducted to determine the effect of nitrogen doses (0, 3, 6, 9, 12 and 15 N kg da-1) on yield and quality traits of common sunflower (Helianthus annuus L.) cultivars (Isera, C-70165 and Teknosol) with different growth periods under ecological conditions of Erzurum Province of Turkey in 2011 and 2012. Experiments were carried out in the Randomized Complete Blocks Design with three replications. Plant height, head diameter, kernel ratio, seed yield, thousand seed weight, oil yield, oil content, protein content and harvest index were investigated. The highest seed yield (341.1 kg da-1), thousand seed weight (65.2 g) and head diameter (17.4 cm) were obtained from 15 kg da-1 treatment of Isera (early) cultivar; the highest oil content (45.2%), oil yield (132.0 kg da-1 ) and plant height (147.7 cm) were respectively observed in 3 kg da-1 treatment of C-70165 (medium early), Isera and Teknosol (late) cultivars; the highest protein content (27.2%) was observed in 12 kg da-1 nitrogen treatment of Teknosol cultivar; the highest harvest index (38.5%) was obtained from 9 kg da-1 nitrogen treatment of Isera cultivar. While the effects of nitrogen doses on oil content were irregular, nitrogen doses had positive effects on seed yield.Keywords: Nitrogen, Harvest index, Helianthus annuus, Protein content, Seed yield, Oil content