Humidity regulation in fuel cells utilizing bulk mass transfer and membrane-based methodologies have drawbacks and limitations, which are undesirable during fuel cell operation. In this work, we demonstrate a rapid and nearly accurate humidity control by mixing of dry and humidified gas streams for tracking predefined relative humidity set points. The humidity responses from the mixed stream could track various relative humidity profiles when coupled with feedback to PI and PID control algorithms. A discussion on the usefulness of this method for controlling the humidification of fuel cell inlet gases, its effectiveness and limitations under high frequency operation are provided. © 2018 Hydrogen Energy Publications LLC