A number of studies have demonstrated a strong correlation between exhaled breath components and specific diseases. Accurate detection of specific volatile organic compounds (VOCs) can thus provide essential information for screening and diagnostic tests. For instance, the acetone concentration in exhaled breath of diabetes is much higher than that of healthy people (below than 1.1 ppm) and the CO concentration of people who smoke a pack of cigarettes per day is ~20 ppm where a nonsmoker is only less than 8 ppm. In this work, we have successfully synthesized a series of conducting polymer functionalized In2O3 nanostructures for sensing low-concentration VOCs. To achieve the required sensing performance, a series of conducting polymers functionalized In2O3 nanostructures with a high surface-to-volume ratio and porosity were successfully synthesized through hydrolysis of In2Cl3 in NaBH4 aqueous solution at room temperature with the subsequent heat treatments. It was found that the novel organic-inorganic heterogeneous nanocomposites exhibit a high sensitivity and an excellent selectivity for specific VOCs, which evidently originated from the essential role of organic functional groups of the conducting polymer.