Growth and endogenous gibberellin activities of spinach in summer cropping under near-ultraviolet eliminating polyvinyl chloride films (UVE) were examined in comparison with those under near-ultraviolet transmitting polyvinyl chloride films (UVT). Growth was more vigorous and the yield was higher under UVE than under UVT. Endogenous gibberellin activities were also higher under UVE than those under UVT at the period of active growth of the plants. The close relationship between the increase in gibberellin activities and the enhancement of the spinach growth under UVE was indicated.