Measurements of the fluctuating temperature in a heated round turbulent free jet have been performed with the aid of a fine wire thermocouple compensated for the effects of thermal inertia. The use of particularly fine thermocouple wires (12.7 μm in diameter) and of digital signal processing represent special features of the experiment. Data are reported for the mean, rms, probability density function, spatial correlation, energy spectrum and, with some reservation, dissipation of the fluctuating temperature. Where possible these are compared with the data of other workers.