The current‐voltage characteristics of germanium tunnel diodes with phonon assisted current predominant have been measured for reverse biases at 297°K. The tunneling exponent is deduced from the data and found to be in agreement with that obtained from high pressure experiments. The value of the pre‐exponential factor obtained from both experiments is much larger than predicted by theory. Calculations of the tunneling current which take into account nonparabolic effects of the energy band structure and the electric field variation with position in the junction are presented and compared with experiment. The results of current‐voltage measurements on germanium diodes with non‐phonon current predominant are also presented and discussed.