The aim of this study was to examine the prevalence and clinicopathological significance of K-RAS oncogene activation in endometrial carcinoma and atypical hyperplasia. We analysed K-RAS point mutation and gene amplification in 55 endometrial carcinomas using polymerase chain reaction associated with restriction fragment length polymorphism and genomic differential polymerase chain reaction. Point mutations at codon 12 of K-RAS oncogene were identified in 8 of 55 (14.5%) tumour specimens. In addition, we were unable to detect any K-RAS gene amplification in any of the endometrial carcinomas studied. No correlation was found between K-RAS gene mutation and age at onset, histological subtype, grade of differentiation, clinical stage or current patient status. We conclude that K-RAS mutation is a relatively common event in endometrial carcinomas, but with no clear prognostic value.