This study examines the effects of different partial root zone drying and deficit irrigation regimes on seed and oil yield quality and water use of drip-irrigated sunflower under field conditions in 2006 and 2007 in the eastern Mediterranean region of Turkey. Irrigation regimes consisted of full irrigation (FI-100) and three deficit irrigation treatments (DI-25, DI-50, DI-75), and partial root zone drying (PRD-50) and rain-fed treatment (RF). Irrigation regimes significantly (P < 0.01) influenced sunflower seed and oil yields and yield components. Although PRD-50 received about 36% less irrigation water as compared to FI-100, sunflower yield was reduced by an average of 15%. PRD-50 produced higher seed and oil yield than DI-50. Irrigation regimes had significantly different effects on yield components and some quality parameters such as the head diameter, number of seeds per head, 1000 seed weight and oil, and plant height at harvest. Yield reduction was mainly due to a lower number of seeds per head and lower seed weights. The saturated (palmitic and stearic acid) and unsaturated (oleic and linoleic acid) fatty acid contents were significantly affected by water stress. The PRD-50 treatment resulted in highest WUE (1.0 kg m(-3)) and IWUE (1.4 kg m(-3)) in both growing seasons. The results revealed that under a water scarcity situation, PRD-50 is an acceptable irrigation strategy to increase sunflower yield and quality. Copyright (C) 2010 John Wiley & Sons, Ltd.