Introduction Kras it is considered one of the most important biomarkers for colon cancer. The determination of this biomarkers have a considerable value for early detection of colon cancer especially at early stages of this disease and it has strong impact for improving the health state for patients suffering from this disease. Therefore, it is very important to design a sensor for the detection of Kras. Experimental Proposed amperometric sensors were designed for the determination of Kras. The sensors were based on graphite and graphene powders with electroactive modifiers such as porphyrins and azulenes. Results and discussion Very low concentrations of Kras biomarkers were reached by utilizing the proposed amperometric sensors. These limits are in the range of early detection, but can also allow the assay of Kras in stages 3 or 4 of the colon cancer. The recovery tests performed proved the convenient of these sensors for the early detection of Kras in whole blood samples. Conclusions The determination of Kras by using the proposed amperometric sensors based on physical immobilization of porphyrins and azulenes in graphite and graphene based pastes revealed excellent results that can be used as a reliable method for the assessment of Kras in whole blood samples.