A remote method was developed for monitoring leaf transpiration rate and stomatal resistance on a real-time basis. The method utilized leaf temperatures measured with an infrared radiometer as an integral input for a model to compute those parameters. The model was based on the energy balance of a plant leaf, accounting for moisture transfer processes in the stomata and boundary layer. Remotely determined transpiration rates and stomatal resistance in maize leaves in the field were compared with those measured with a steady-state porometer. The corresponding values obtained from the two methods were linearly correlated, while no specific relationship was found between leaf-air temperature differential and stomatal resistance or transpiration. The porometer transpiration rates were slightly higher than those obtained by the “remote” method with a correlation coefficient of 0.93**, probably because the air in the porometer cuvette was drier consistently than the ambient air. The stomatal resistance values from the two methods fell on the 1:1 line with a high correlation coefficient (0.96**), suggesting that the “remote” method produce excellent estimates of actual stomatal resistance.