Aspects of a method and system for power supply adjustment for polar modulation of an RF signal are provided. In an RF transmitter, a signal representative of an amplitude of a pair of phase-quadrature baseband signals may be generated, and a voltage and/or current supplied to one or more components of said RF transmitter may be controlled based on said generated signal. Additionally, aspects of the invention may enable dividing each signal of said pair of baseband signals by said generated signal, up-converting the divided signals, and combining the up-converted signals to generate a phase modulated RF signal. The one or more components may comprise, for example, one or more amplifiers, and/or one or more mixers. The generated signal may result from squaring each signal of the pair of baseband signals and calculating a square root of a sum of the squared signals.