This study was conducted at El- Baramoon Research Farm, Mansoura Horticulture Research Station, HRI, ARC, Egypt during two successive winter seasons of 2013/2014 and 2014/2015. The objective of this study was to determine the effect of harvesting stages on the quality of fennel fruits. The experimental design was a randomized complete block design with four replications. Variations of fruit yield per plant, seed index, germination behavior and essential oil content and composition were studied during different maturation stages. The obtained results indicated that, maximum yield and quality of fennel fruits in terms of fruit yield, thousand fruit weight (seed index) and germination percentage were reached their maximum at stage 4 (the primary umbel was matured completely). Essential oil percentage was higher in the early harvesting stages, while essential oil yield per plant reached its maximum when fruits were harvested at stage 4. The composition of volatile components of the essential oils extracted from fruits at eight stages of maturity was studied by gas chromatography andfive main compounds were identified. The first major component was Methyl chavicol ranged from 72.34% to 88.67% and increased gradually with increasing fruit age to reach its maximum at stage8 (the primary umbels were falling). It could be recommended from the previous results the highest fruit yield and quality as well as essential oil yield were obtained in fennel when fruits harvested at stage 4 under the condition of this experiment.