This paper describes the experience of the development and deployment of an expert system for cucumber production management under plastic tunnel (CUPTEX). CUPTEX is intended to be used by agricultural extension service within the Egyptian Ministry of Agriculture (MOA), and by private sector. The main objective of developing such systems is to transfer new technology in agromanagement to farmers through packaging this technology using expert systems. This will lead to increasing the production and hence the national income, on one hand, and reducing the production cost on the other hand. CUPTEX was developed using a methodology based on KADS. CUPTEX is composed of three expert systems for fertigation, plant care, and disorder remediation. The validation of CUPTEX has revealed that it over performs a group of experts in different specialties. Although the direct payoff is not the main objective of the development, experimenting CUPTEX in two research sites has revealed that approximately 26% increase in production, and 15% decrease in direct cost have been attained. These results show that CUPTEX could pay off approximately 60% of the development cost in 4 months if it is used to manage the plastic tunnels cultivating cucumber in the five sites in which it was deployed. CUPTEX could also pay off its cost by charging a nominal price for each copy deployed to private sector farmers. The commitment of MOA to expert systems technology helped and will help in maintaining the knowledge base of CUPTEX. The methodology developed while building CUPTEX have been and will be used for other crops.