The purpose of this paper is to present and document the differences discovered when comparing the two accident dose codes FUSEDOSE and MACCS2. Each code's methodology is first discussed. With this background, the important comparison parameters are discussed and the resulting differences are presented. It is not the purpose of this paper to draw conclusions as to which code is more reliable but, it is hoped that the data presented will help in deciding upon further actions to be taken, if at all, to improve accident dose calculations.