The biomedical topic that attracted the early interest of engineers is that of electrocardiography. It is the most useful noninvasive medical diagnostic tests and is in very wide use (an estimated 200 million ECG s taken each year). Its technological challenge is to improve performance by increasing the number of simultaneously recorded signal, raising the signal to noise ratio. The increase in data acquisition rate also provides new challenges in the design of recording systems including the application of methods of data compression. The electrocardiogram has the considerable diagnostic significance, and applications of ECG monitoring are diverse and in wide use. Different types of noise due do which ECG gets corrupted. The various noise types considered were 50Hz power line interference, base line drift due to respiration, abrupt base line shifts, and a composite noise constructed from all of the other noise types. Different digital filter structures are presented in the paper to eliminate these diverse forms of noise sources and their performance is discussed with reference to efficiency, distortion of the signal. The ECG signals used in this study were obtained by designing twelve lead instrumentation amplifier. The design system leads to prototype device for the ECG. To remove low frequency and Power line interference in the ECG signal, digital filter based on least mean squares has been implemented and presented in the paper.