An agricultural spray nozzle and nozzle spray volume selection expert system (ASNS) was designed and developed on a Personal Computer with minimum hardware and software requirements. The ASNS consisted of inference engine and knowledge base. The knowledge base contained facts and production rules. The expert system was faster by at least a factor of 10 and 60 as compared to an expert and a novice respectively, for performing the same task through traditional means. It's decision were more consistent and the system was available 24 hours. ASNS was user friendly, transparent, and handled certainly factors. It could be modified and updated without changing the control structure. It could also explain the reasoning behind it's recommendation.