An expert system (ES) was constructed for the diagnoses and management of coffee (Coffea arabica) diseases. The ES contained 229 rules (if-then), 182 photographs comparing 13 diseases, 8 nutrient deficiencies, 9 pests, 4 species of nematodes, 12 injuries, a glossary of technical terms, disease descriptions, a movie on how to make Bourdeaux mixture and another one on bacterial streaming. The evaluation was divided into verification and validation.