The purpose of this study was to investigate the effects of different harvesting stages on some yield and quality characteristics of lemon balm (Melissa officinalis L.) during the 2013 and 2014 growing seasons in Odemis, Izmir, Western Turkey. The experiment was established as a randomized blocks design with four replications and the plants were harvested at three growth periods such as pre florescence (in May), during florescence (in August) and post-florescence (in November). Plant height, fresh herb yield, dry herb yield, dry leaf yield, dry stem yield, essential oil content and constituents were determined. Statistical analyses showed that the plant height, fresh herb yield, dry herb yield, dry stem yield and essential oil content were all affected by the harvest stages. Mean value of the plant height ranged between 76.94-91.60 cm, fresh herb yield was 21980.9-39941.5 kg ha(-1), dry herb yield was 5955.8-91358.0 kg ha(-1), dry leaf yield was 717.4-1076.8 kgha(-1) and dry stem yield was 524.3-939.2 kg ha(-1). The total essential oil content ranged between 0.27-0.36% and the highest content was provided from the florescence stage of the plant. The main constituent of the essential oil was determined as E-Citral and ranged between 25.90-37.74% of the total and the highest content was also obtained from the florescence stage. Z-Citral and Caryophyllene oxide were identified as other components of the lemon balm essential oil. (C) 2016 Elsevier B.V. All rights reserved.