The fill factor of a solar cell depends upon the series resistance, reverse saturation current, diode quality factor, operating current and voltage, Since the series resistance itself depends upon the operating current (or voltage), it makes the evaluation of fill factor very complicated. In this paper, we have evaluated the fill factor of a solar cell, taking into account operating current dependence of the series resistance. (C) 2002 Elsevier Science B.V. All rights reserved.