Fatigue behavior of amorphous polystyrene (PS) under various cyclic strain conditions was investigated on the basis of nonlinear dynamic viscoelastic measurement at various ambient temperatures. The degree of nonlinear viscoelasticity under tension-compression type cyclic strain was greater than that under tension or compression type ones. The longest fatigue lifetime and the shortest one were observed under compression and tension type fatigue tests, respectively. The fatigue lifetime decreased with an increase in nonlinear viscoelastic parameter (NVP) in the case of the same type of cyclic strain conditions.