Radiation oncology requires appropriate planning of both target volume and location. The correct calculation of the target volume as well as the precise location of critical anatomic structures is vitally important to ensure the success of treatment. Treatment planning systems (TPS) are used in radiation teletherapy to simulate the projection of the field, its shape and the distribution of the absorbed dose over the volume of interest. This allows maximization of the absorbed dose in the target tumor and minimizes unnecessary exposure to other tissues. A quality assurance program is also important to ensure the effectiveness of treatment. In Brazil, in 2000, the Ministry of Health instituted a protocol to optimize the quality control associated with radiation oncology. In 2004, the International Atomic Energy Agency established a specific protocol for quality control procedures for TPS. However, an appropriate methodology to comply with these quality control procedures is needed. We propose a methodology for assessing the quality control tasks used in treatment planning systems. This methodology will evaluate the capacity of TPS to use the data generated by computed tomography and the table scanner to determine the appropriate distribution of the absorbed dose over the volume of interest.