Herein, we describe the design, fabrication and gas sensing tests of p-Co ₃O ₄/n-ZnO nanocomposites. Specifically, arrays of 〈001〉 oriented ZnO nanoparticles were grown on alumina substrates by plasma enhanced-chemical vapor deposition (PECVD) and used as templates for the subsequent PECVD of Co ₃O ₄ nanograins. Structural, morphological and compositional analyses evidenced the successful formation of pure and high-area nanocomposites with a tailored overdispersion of Co ₃O ₄ particles on ZnO and an intimate contact between the two oxides. Preliminary functional tests for the detection of flammable/toxic analytes (CH ₃COCH ₃, CH ₃CH ₂OH, NO ₂) indicated promising sensing responses and the possibility of discriminating between reducing and oxidizing species as a function of the operating temperature.