Abstract: Method for detecting Ki-ras mutations in exon I, codon 12 to 13 in samples of tissue, tumor tissue, tissue secretions, excretions, expectorates, blood and lymph by two subsequent PCR amplifications comprising a regular PCR amplification and an allele specific amplification and wherein the identification step may comprise a Phast Gel SSCP, characterized in that by a specific selection of oligoprimers in the combination of two PCR amplifications and the Phast Gel identification or in the combination of the said regular PCR amplification and Phast Gel identification produced direct detection of the mutations is produced.