We describe the first field applications of a new multifunctional foaming agent (MFA) for production enhancement in oil wells with gas lift. The tests were conducted in three wells with water cuts from 40 to 90%, depth (>5000 m), bottomhole temperature (150°C), and brine hardness and salinity up to 180,000 ppm and 310,000 ppm TDS, respectively. The MFA was coinjected with lift gas via the annulus and generated foam downhole as it mixed with reservoir fluids in the tubing. Tested MFA concentrations ranged from 160 to 750 ppm. The field tests demonstrated that the MFA was able to increase the oil production for a fixed gas lift injection volume. The MFA also enabled to reduce lift gas consumption, while maintaining or even increasing the original oil production.