In this letter, a method for finding the compact fractional Fourier domains is presented. As a measure of compactness, we take the l(1)-norm. It is proposed that there exists at least one fractional Fourier domain in which l(1)-norm of the transformed signal is minimum. A coarse-to-fine grid search strategy is adopted to find the optimum fractional Fourier transform angle thatmakes l(1)-norm minimum with low computational cost. Extensive simulation results validate the proposed method.