Measurements were made at New Delhi (India) on wheat (Triticum aestivum L.) and mungbean (Vigna radiata L.) crops growing during the winter and summer seasons respectively, to evaluate the use of the equation of Bartholic, Namken and Wiegand (1970) for estimating daytime evapotranspiration from a single measured canopy temperature. Measurements on eleven days indicated that a single observation of the canopy temperature taken at any time between noon and 2 p.m. could be used to compute daytime evapotranspiration with an error (underestimate) of less than 27% as compared with values measured by the Bowen ratio method. The regression equation ET0 = 0.618 + 0.96 ET1 has a coefficient of determination of 0.927 and can be used to relate daytime evapotranspiration by the Bowen ratio method (ET0) to that estimated by the Bartholic-Namken-Wiegand equation (ET1) for wheat and mung bean crops grown under adequately watered conditions in the New Delhi region.