In this talk, we will present a new explanation of the mysterious Fast Radio Bursts (FRBs) in terms of axion star-neutron star encounters. As a dense axion star moves through the resonant conversion region of a neutron star magnetosphere, where the plasma-induced photon mass becomes equal to the axion mass, the axions can efficiently convert into photons, giving rise to an intense, transient radio signal. The energy released is determined by the axion star mass and conversion probability. The peak frequency of the emitted radio signal is fixed by the axion mass, while cosmological redshift and Doppler shift could give rise to a wide range of frequencies. In particular, we will show that a dense axion star with a mass ∼ 10^-13 solar mass and composed of ∼ 10 μeV axions can account for most of the non-repeating FRBs in a wide frequency range. We will also comment on the repeating FRBs and on future tests of our hypothesis.