During 1972 the occurence of sterile spikelets in wheat at the Monte Alegre do Sul and Pindamonhangaba Experiment Stations was determined. The occurrence of sterile spikelets was correlated with high temperature and low relative humidity during the cultivars flowering stage. The correlation coefficients between sterile spikelets and temperature during the flowering stage were +0,9681*** (Monte Alegre do Sul) and +0,8753*** (Pindamonhangaba). The correlation coefficients between sterile spikelets and relative humidity during the flowering period were -0,9572*** (Monte Alegre do Sul) and -0,9112*** (Pindamonhangaba).