This study was performed to determine the effects of feeding pollen cake containing honeybee royal jelly on Bombus terrestris colony development. In total, 125 bumblebee queens, 68 of which were fed pollen cake containing 10% royal jelly and 57 of which were fed normal pollen cake, were used. We found that 84% of the queens fed pollen cake containing royal jelly and 82% of those fed normal pollen cake laid eggs; 56% of the queens fed normal pollen cake established colonies, whereas queens fed pollen cake containing royal jelly did not establish any colonies and their larvae died. The results showed that feeding pollen cake containing royal jelly had a negative effect on bumblebee larval development.