Abstract: Electromyography (EMG) is the study about the function of muscles, and today it have many applications in biomedical and clinical purposes. The EMG signal contains two sources during the myoelectrical simulation which are the useful electrical response of the muscles and the noise in the signal. The noises can occur from either technical sources (power line noise) or from biological sources (ECG). The noises in the system must be carefully studied, as this will interrupt the analysis of the muscular activity. This paper discuss about various types of noises that affects EMG signal and also some of the basic noise removal techniques.