A fully integrated CMOS electrocardiogram (ECG) Analog Front-End (AFE) is presented. The ECG AFE adopts an AC-coupled chopper-stabilized instrumentation amplifier (IA) structure to achieve the low input referred noise. An input common mode feedback (ICMFB) amplifier, DC servo loop (DSL), programmable capacitor array are added to enhance the IA performance. The overall gain, band width can be trimmed using configurable capacitor and resistor. The ECG AFE is fabricated in 0.18μm 1P4M CMOS process. The core chip size of the ECG AFE without I/O pads is 2.14 mm2. The maximum amplifying gain of the pass band is measured to be 66.91 dB.