A method for measuring polarization-mode dispersion (PMD) on fiber links using four-wave mixing (FWM) generation is presented. This method uses a probe signal to analyze the signal polarization state via FWM generation. The FWM power transfer function is derived in terms of the Stokes parameters, and is validated using both simulated and experimental results. Based on this transfer function, PMD measurements are presented that agree well with the actual PMD values. Compared to the traditional frequency-domain methods, this new method does not require a motionless condition for the measurement apparatus.