Research has been carried out with the aim of designing a carbon monoxide (CO) gas sensor based on an interdigital electrode (IDE) and PVA/TiO2 nanofibers, knowing the response of an IDE sensor without PVA/TiO2 nanofibers to CO gas and knowing the sensitivity of IDE-based sensors and PVA/TiO2 nanofibers to CO gas. CO gas. The principle used is chemiresistor, if there is an interaction between CO gas and PVA/TiO2 nanofibers, it results in a change in the resistance of the sensor. Manufacture of PVA/TiO2 nanofibers using the electrospinning method. In this study, the variation of TiO2 concentration was 0.5 w/v. The IDE sensor and PVA/TiO2 nanofiber have demonstrated the chemiresistor principle because with increasing CO gas content the resistance decreases. IDE sensors without PVA/TiO2 nanofibers cannot respond to CO gas.