A two-year study was conducted to determine plant biomass, plant height, seed yield, fatty acid and essential oil contents and essential oil composition of coriander (Coriandrum sativum L.) cultivars across different irrigation levels in a semiarid climate area of Kayseri, Turkey. The experimental design was a randomized complete block arranged in split plot arrangement with three replications. The main plots were cultivars Gurbuz and Aslan, the subplots were irrigation levels 0, 25, 50, 75 and 100%, assigned as S0, S1, S2, S3 and S4, respectively. Growth season of autumn sowed corianders lasted about 270 days and the plant consumed water between 265-680 mm according to the applied water level. Coriander is a slightly sensitive plant to water stress since seed yield response factor of both coriander cultivars were found slightly higher than 1. Higher seed and essential oil yields were obtained with elevated water application. Water stress caused decrease in coriander biomass, plant height, seed yield and essential oil yield. Fatty acid and essential oil ratios were not changed significantly by water stress. Main essential oil component linalool was not changed with changing water amounts. Non-stable differences in essential oil components were observed between coriander varieties in both years. In coriander cultivation, timely irrigation with enough water is very crucial to obtain the highest seed yield and essential oil yield.