Nowadays, clinical decision support system become a part of daily life. Accurate
diagnosis of liver cirrhosis helps in avoiding medical problems which may lead to
death. The aim of the study is to build a fuzzy expert system for the diagnosis of liver
fibrosis-stage (DLFS). The system uses machine learning tools and data mining statics
to discover fuzzy rules, which help physicians to provide a fast and accurate
diagnosis. The experimental have been performed on real dataset from clinical data
sheets for 119 patients infected by chronic HCV. The evaluation results showed that
the system identify liver fibrosis-stage with high degree of accuracy 95.7% and may
decrease the need for liver biopsy.