An attempt has been made for the determination of diode parameters viz, shunt resistance R(sh), series resistance R(s), diode ideality factor n and reverse saturation current density J(0) of three solar modules: a-Si 47-37, a-Si 51-13 and CdTe 14407. In this regard, two approaches namely (A) and (B) reported by Khan et al. (2010) have been used to determine all the four diode parameters Rsh, R n and J(0). The data of slopes of J-V curve at open circuit conditions (m(oc)) and open circuit voltage (V(oc)) at different illumination intensities obtained by Del Cueto (1998) for two a-Si and one CdTe solar modules have been used to determine the above diode parameters. The determined values of diode parameters have been used to generate the theoretical J-V curves. The theoretical fill factor (FF) and V(oc) have been calculated from the theoretical J-V curves and are plotted along with the experimental FF and V(oc) values. The theoretical values of FF and V(oc) obtained by the approach (B) of method of Khan et al. (2010) are in good agreement with the experimental values. (C) 2011 Elsevier Ltd. All rights reserved.