In this paper, the sensitivity constant (C_f) of an electrochemical quartz crystal microbalance (EQCM) is determined through a calibration procedure using potentiostatic electrodeposition of Tl, Pb, Ag and Cu films onto a gold electrode. In the literature some researchers have proposed the use for example of thallium or lead films on gold electrodes to obtain the sensitivity constant for calibration and to keep these electrodes reusable. However, it is not clear if with these metals the C_f values are reliable, given the fact that generally silver or Cu films are employed for this purpose. One of the most significant results reached in this work was that C_f values obtained with Tl and Pb films are dependent on both the imposed potential and the thickness of deposits. In addition, the C_f values obtained with these metals were found to be very close to the theoretical value as those obtained with silver films.