This paper presents the study of electromagnetic interference effect from power line noise in Malaysia to electrocardiograph (ECG) signal. The study includes the design of ECG circuits that is used to eliminate the power line noise from the signal. The ECG system basically is a combination of instrumentation amplifier, high pass filter, low pass filter, and notch filter. There are several other circuits developed in this study which are voltage reference, ac-coupling circuit and low pass filter for voltage input from USB power supply. The usage of faraday shield is to get the real ECG signal without electromagnetic interference from the power line. Faraday shield prevents a range of outside noise from coming into the shield. Therefore, the data taken inside the faraday shield is free from 50Hz noise without using notch filter. The result of this study showed that faraday shield can eliminate 50Hz power line noise in ECG signal.