A method of fabricating a complementary metal oxide semiconductor (CMOS) device is provided. A first conductive type MOS transistor including a source/drain region using a semiconductor compound as major material is formed in a first region of a substrate. A second conductive type MOS transistor is formed in a second region of the substrate. Next, a pre-amorphous implantation (PAI) process is performed to amorphize a gate conductive layer of the second conductive type MOS transistor. Thereafter, a stress-transfer-scheme (STS) is formed on the substrate in the second region to generate a stress in the gate conductive layer. Afterwards, a rapid thermal annealing (RTA) process is performed to activate the dopants in the source/drain region. Then, the STS is removed.