Summary form only given. Agricultural land drainage planning is a difficult and complex task, which relies heavily on varies of factors (e.g. engineering parameters, environment parameters, drainage theories, the knowledge of an agricultural land drainage planning expert.....). Many packages are implemented to do this task. Nevertheless, its procedure still requires the involvement of experts to choose the right parameters and model. In this paper, we present a tool developed using knowledge-based system and a geographic information system (GIS) approaches for planning agricultural land drainage. The proposed approach combines heuristic rules obtained from domain experts, to perform essential tasks in agricultural land drainage. Our tool includes a knowledge-based system, an elaborate interface, a geodatabase and a geographic information system GIS. The knowledge-based is represented in "production rules". The inference engine is a backward chaining. The GIS is represented by ARCVIEW, ARC/INFO. The proposed tool has been tested using a case study for the district of delta and middle Egypt. Results demonstrate the effectiveness and flexibility of the proposed methodology in tackling the important problem of agricultural land drainage planning.