Öz A concept of the integration of the interpolative and extrapolative calibration methods - commonly used in analytical chemistry - is presented, i.e. it is proposed to perform both methods according to a single calibration procedure. Such an approach allows one to obtain two estimations of the analyte concentration in a sample and to verify it in terms of accuracy. It is suggested to execute the integrated calibration method by the flow injection technique in accordance with two different procedures. The instrumental flow systems designed for this purpose are shown. The principle of both procedural versions is revealed and the specificity of them is discussed. The reasons are explained why the method is worth to be brought into the analytical practice