The present invention relates to a method for detecting c.-124 C>T and c.-146 C>T mutations in the Htert gene promoter. The method uses reaction compositions that comprise amplification primers and genotyping probes. Another aspect of this invention relates to the primers and probes used to implement the aforementioned method, with sequences, identified as SEQ ID no.1 to SEQ ID no.6, that displayhigh specificity for these mutations, and to the compositions containing these primers and probes. The present invention further relates to a kit comprising the above-mentioned compositions for detecting c.-124 C>T and c.-146 C>T mutations in the Htert gene promoter by carrying out the method according to the present invention. The method, gene sequences, compositions and kit of the present invention can be advantageously used for detecting trace amounts of c.-124 C>T and c.-146 C>T mutations in biological samples, due to their high sensitivity and specificity for such mutations. The present invention can thus be applied in early detection, identification, detection of recurrence or prediction and monitoring of diseases associated with this type of mutations, such as bladder carcinomas, thyroid carcinomas, squamous cell carcinomas, basal cell carcinomas, melanomas, gliomas and hepatocellular carcinomas, inter alia, and ultimately provide the basis for defining a suitable treatment. Thus, the present invention pertains to the technical fields of medicine, pharmaceutics, molecular biology, biochemistry, human genetics and the like.