Determining the difference between the elevations of points by geometric leveling method using leveling cameras is one of the most commonly used methods for implementation of developmental projects in the country. Implementation of projects such as preparation of longitudinal profiles of rivers, roads, power transmission lines, etc. requires leveling. In addition, this method is used in the implementation of nation-wide leveling networks and creation of base points (ground control) for converting aerial and satellite images into maps. Despite the extreme accuracy of the traditional leveling method, implementation of this method is time-consuming and costly, and so far no alternative has been considered by surveyors as feasible. The purpose of this study was to determine the relative accuracy of the GPS-based leveling method using the available Iranian Gravitational Geoid file in different parts of the country. The results of the research confirm the possibility of using this method to achieve the accuracy of normal leveling (of third degree) in most regions of the country.