The exact knowledge of stem cutting energy is one of the main parameters for optimizing design of cutting elements in harvesting machines. In this study, cutting energy of rice stem at different internode positions was examined. Four common Iranian rice varieties, namely Khazar, Hybrid and Dorfak (high-yielding and lodging tolerance varieties) and Tarom (local and lodging susceptible variety) were used in the experiment. A pendulum impact type testing apparatus was fabricated and used for the tests. The results indicated that cutting energy significantly (p