The objective of this study is to design a fertigation program for bean (Phaseolus vulgaris L.) using the expert system (ES).To achieve the objective of this study, the following steps were required: i. identification of the problem ii. analysis of the information iii. characterizing the variables of the key factors and qualifiers. The study involved also a comparison between the ES program outputs and the corresponding ones recommended by the Ministry of Agriculture. To establish such a comparative study, a field experiment was executed on bean plant after dividing the filed of study into two sections. In the first, the experimental work was carried out using the ES fertigation management, while in the second section, the well known “CROPWAT Program”, was used for the scheduling of the irrigation together with the traditional methods of fertigation outlined by the Ministry of Agriculture, Egypt. The results of comparison assured the superiority of the ES over the other traditional one, where higher values of water use efficiency “WUE” and nutrient use efficiency “NUE” were achived by the former than the latter.