Immediate early response gene X-1 (IEX-1) gene was discovered by Charles in 1993, which plays an important role in regulating apoptosis. Previous studies demonstrated that IEX-1 gene was expressed in a variety of human tissues and played an important role in regulating apoptosis and cell growth through a positive or negative way. It can inhibit cell growth and apoptosis. However, it can also promote cell apoptosis. There is evidence that IEX-1 is involved in viral infections and cardiovascular diseases and it is highly expressed in many tumor tissues. The regulatory mechanisms for IEX-1 under normal and pathophysiological conditions are complicated and remain largely unknown. In this paper, we reviewed the recent progress of IEX-1 in different disease models.