Scaling the supply voltage (VDD) and threshold voltage (VTH) for minimizing the energy consumption of processors dynamically is highly desired for applications such as wireless sensor network and Internet of Things (IoT). In this paper, we refer to the pair of VDD and VTH, which minimizes the energy consumption of the processor under a given operating condition, as a minimum energy point (MEP). Since the MEP is heavily dependent on an operating condition determined by a chip temperature, an activity factor, and a performance required for the processor, it is not very easy to closely track the MEP at run-time. In this paper, a simple but effective algorithm for dynamically tracking the MEP of a processor under a situation that the operating condition of the processor dynamically varies is proposed. Gate-level simulation of a 32-bit RISC processor in a 65nm process demonstrates that the proposed algorithm tracks the MEP under a wide variety of dynamically changing operating conditions.