Heart related problems are increasing day by day and Electrocardiogram (ECG) signal are very important in diagnosis of heart related problems. There are various artifacts which get added in these signals and change the original signal, therefore there is a need of removal of these artifacts from the original signal. ECG signals are very low frequency signals of about 0.5 Hz-100Hz and digital filters are very efficient for noise removal of such low frequency signals. In this paper we have studied Finite Impulse Response (FIR) filter based on various windows and Infinite Impulse Response (IIR) filters for noise removal of ECG signal and from the results of papers it is seen that kaiser window based FIR filter is better to remove artifacts from ECG signals.