A BiCMOS device with enhanced performance by mechanical uniaxial strain is provided. A first embodiment of the present invention includes an NMOS transistor, a PMOS transistor, and a bipolar transistor formed on different areas of the substrate. A first contact etch stop layer with tensile stress is formed over the NMOS transistor, and a second contact etch stop layer with compressive stress is formed over the PMOS transistor and the bipolar transistor, allowing for an enhancement of each device. Another embodiment has, in addition to the stressed contact etch stop layers, strained channel regions in the PMOS transistor and the NMOS transistor, and a strained base in the BJT.