© 2019 International Society for Horticultural Science. All rights reserved.Melatonin (Me) which has found in the roots, leaves, fruits and seed, has important effects in plant growth and development. Melatonin concentrations in plants increase under various stress conditions. Increasing melatonin concentrations provides stress resistance. In this study, the effects of melatonin (100, 75 and 50 ppm) spray on yield and fruit quality were studied in irrigated and non-irrigated pomegranate orchards in Muğla province (Turkey) which is the main pomegranate producing region after Antalya province. Melatonin was applied in full blossoming. Yields such as average fruit weight, average fruit size, fruit juice yield, fruit grain yield and some fruit quality characteristics such as antioxidant activity, total phenolic content, anthocyanin and vitamin C were determined. The maximum average fruit weight was observed in 75 ppm Me in irrigated trees (374 g) and 100 ppm Me non-irrigated fruits (304 g). The maximum antioxidant activity in fruits was measured in 100 ppm Me irrigated (26.7 µL mL-1) and in 100 ppm Me non-irrigated ones (148.7 µL mL-1). Regarding anthocyanin and vitamin C contents, the highest melatonin treatment increased their concentrations.