Multicasting is an important function of wavelength-routing optical communication networks. An all-optical multicasting is presented and experimentally demonstrated based on four-wave mixing (FWM) in highly nonlinear fibers. An input signal with data information together with a pump are injected into a highly nonlinear fiber and two idlers with new frequencies can be generated through two degenerate FWM processes, which carry the same data information as the input signal. The single input signal is copied to two channels and the pump can also be modulated by this data. The advantage of this scheme consists in the simple configuration, where only a single pump is needed and no other injected lights are required, the uniform powers and tunable wavelengths of the multicasting signals, and the capacity to further increase multicasting channel number.