Abstract: The present study aimed to evaluate the effect of different harvesting times on the quality of barley seed cultivars and to identify the best and most suitable barley harvesting stage for producing the most desirable seeds. To do so, a factorial experiment in a completely randomized block design with four replications was undertaken. The experimental factorials included six barley cultivars (Makoee, Dide, ADC-1, Bahman, Yusef and ADC-20) and 10 harvesting time stages (211 days after emergence and one harvest every 5 days up to 256 days after emergence). All six cultivars were concurrently cultivated in 2011 and two irrigations were performed for the initial emergence. The attributes to be studied were thousand-seed weight, seedling dry weight, seed vigour index, mean germination time, germination rate, percentage of viable seeds and electrical conductivity. The results indicated that the effects of different harvesting times and cultivar effect on all studied characteristics (thousand-seed weight, seedling dry weight, seed vigour index, mean germination time, germination rate, percentage of viable seeds and electrical conductivity) were significant (p<0.05). Most of the cultivars reached the maximum germination and seedling growth rate 241 days after emergence. Furthermore, the results highlighted the significance of the reciprocal effect of harvesting time×cultivar on electrical conductivity and thousand-seed weight. In general, the results suggested that the best harvesting time in most cultivars was the seventh harvest (241 days after emergence). In addition, electrical connectivity and thousand-seed weight could be utilized as useful indexes for determining the harvesting time.