This work aims to compare two deposition methods to highlight the strong influence of the induced morphology on the sensitive film conductivity. Lanthanum oxycarbonate films have been deposited by drop coating and screen printing for carbon dioxide detection. The measurements are based on a change in resistance and provide sensitive responses to carbon dioxide concentrations in a humid environment maintained at 50%. Electrical measurements were made under 5 000 ppm of carbon dioxide in synthetic air. Our results highlighted the close link between the morphology of the sensitive layers and the electrical responses of the sensors, and therefore the need to master the deposition technique.