A technology was developed for manufacturing solid-state semiconductor sensor sensitive to hydrogen peroxide vapors. Gas sensitive nanostructured films made of doped metal oxide SnO2<Co> were manufactured by the high-frequency magnetron sputtering method. The chemical composition of prepared SnO2<Co> targets was analyzed and the thickness of the deposited doped metal oxide film was measured. The morphology of the deposited Co-doped SnO2 film was studied by scanning electron microscopy. The gas sensing characteristics to the different concentrations of hydrogen peroxide vapors at various operating temperatures were also studied. The Co-doped SnO2 sensor showed enough sensitivity to very low concentration of hydrogen peroxide vapors (875 ppb) at the operating temperature of 100 °C. The SnO2<Co> based sensor can be successfully used in medical diagnostic apparatus for determining low concentration of hydrogen peroxide vapors in exhaled air.