A b s t r a c t The performance of bee colonies greatly depends on the quality of the queens. The current research was conducted at the apiary of the Faculty of Agriculture, Zanjan University, in Zanjan, Iran. Together, 24 rearing colonies were assigned to 4 grafting larvae age groups: 1-day-old, 2-day-old, 3-day-old, and emergency queens. Two feeding groups, fed and not fed, were created. The effects of reared queens on biological characteristics and performance of honeybee colonies (Apis mellifera meda) headed by those queens were measured. Age of grafted larvae significantly influenced the results. The performance ratios of the most efficient colonies headed by queens reared from 1-day-old larvae compared with the least-efficient queens reared from 3-day-old larvae were 118% in brood production, 140% in bee population, and 154% in honey production. However, the age of grafted larvae did not affect colony defense behavior. Supplemental feeding of rearing colonies increased brood production to 111%, bee population to 116%, and honey production to 115%. A combination of the effect of age of larvae and supplemental feeding resulted in twice as much honey (12 kg) produced by colonies with queens reared from 1-day-old larvae in fed rearing colonies compared to those with queens raised from 3-day-old larvae in unfed rearing colonies.