Prostate cancer is a common malignancy that develops by structural mutation(s) and/or other genetic alterations in specific genes.The G to T transversions in codon 12 and C to T transitions in codon 13 of KRAS proto-oncogene are predominant point mutations that occur in about 20% of different cancers in human. In the current study it was aimed to investigate the prevalence and predictive significance of KRAS mutations in patients with prostate carcinomas. In a total of 30 fresh tumoural tissue specimens were investigated in patients with prostate carcinoma. All tumoural specimens were histo-pathologically diagnosed and genotyped for codon 12, 13 KRAS point mutations by reverse hybridisation and direct sequencing methods. KRAS mutations were found in 12 (40%) samples with 29 samples deriving from adenocarcinomas and 1 sample was small cell prostate carcinoma. In 1 (3.44%) sample codon 12 was found to be mutated and in 2 (6.8%) samples codon 13 and in 9 (31%) samples combined codon 12 and 13 were found to be mutated particularly in higher grade of tumoural tissues. Our study, based on representative collection of human prostate tumours, indicates that combined mutations in codons 12 and 13 KRAS are relatively infrequent and most commonly occur in prostate carcinomas.