This paper considers Least Mean Square (LMS) algorithm to subsequently modify adabtive filter weights. The corresponding filter is used to cancel noise cused by powerline interfrence contained in Electrocardiograph (ECG) signal. The designen is then implemented on LabView software. The simulation shows that design can recude powerline interfrence. Average powerline noise power contained in the signal is attenuated by more than 20 times. ECG; Last Mean Square; Labview ; Steepest gradient descent; Adaptive Filter; Powerline interfrence