Paraffin embedded tissues from twenty Thai patients with intrahepatic cholangiocarcinomas were studied for K-ras gene mutations at codon 12, 13 and 61 and for p53 gene mutations in exon 5 to 8 using polymerase chain reaction and thermal cycle sequencing. Results showed that point mutations at these regions in K-ras oncogene were not present in all the samples. One case harbored a p53 gene mutation in codon 282 in exon 8, CGG (arginine) to TGG (tryptophan), but the mutation was not found in other patient's tissues with similar histological features.