Hereditary non-polyposis colorectal cancer (HNPCC) is an autosomal dominant inherited disease characterised by almost inevitable development of colorectal carcinoma and/or endometrium and other defined malignancies in affected individuals. HNPCC is caused by a germline mutation in a mismatch repair genes (MMR). The purpose of this review is to summarize current knowledge regarding HNPCC with the focus on recent data on genetic testing, surveillance guidelines and therapy. Available medical databases were searched from 1998 to May 2003 using the keywords "hereditary nonpolyposis colorectal cancer", followed by further search for particular issues. Additional articles were identified through the reference sections of retrieved articles and from personal archive of authors. Approximately 200 papers on HNPCC are published yearly. The major progress in recent research of HNPCC has been made in the area of genetic testing and clinical surveillance. Current guidelines recommend identification of microsatelite instability in a tumour of affected family member followed by germline testing in this person. Once mutation in particular MMR gene is found, screening of all at risk members is recommended. Alternative approach suggests direct germline testing in unaffected family member provided that the testing in affected member is not possible. Annual colonoscopy examinations starting at 20-25 years and gyneacological examination starting at 30-35 years are recommended in all family members at risk. Recent advances in genetic tests and surveillance strategies result in decreased mortality of HNPCC patient.