Abstract: An automated system for rapidly and safely evacuating used fluid from the drain plug opening of a fluid receptacle and replenishing the fluid receptacle with fresh fluid through the same drain plug opening. The automated fluid changing system includes an evacuation means for withdrawing the used fluid from the drain plug opening, a dispensing means for dispensing fresh fluid into the fluid receptacle through the drain plug opening, valve means for controlling the flow of fluids into and out of the fluid receptacle, and electronic control means which is in communication with the valve means, the evacuation means, and the dispensing means for automatically directing each phase of the fluid changing procedure. The evacuation means includes a suction pump for applying a suction force to withdraw the used fluid. The dispenser means includes a pump for dispensing the fluid into the fluid receptacle under pressure.