This experiment was undertaken with the purpose of investigating effect of gibberellin on the growth and electron microscopic ultrastructure of hop(Humulus lupulus var. Hallertau) shoot apex. The results are as follows. 1) The growth of stem in the plots treated with GA(10, 25, and 50ppm) is more predominant than control. The leaves and cones of treated plots turn to pale green. 10ppm plot of GA treatment is the most effective in growth and yield than the others. 2) Under the GA-treated condition, it is believed that the nucleoplasmic index (NP) are higher than the control, and so nucleus, nucleolus, mitochondria, primary cell wall, middle lamella, and etc. tends to be larger than the control. 3) Mitochondria contained in the cell of shoot apex treated with concentration of 10ppm GA was seemed to increases in number and be larger in size than the control.