The conduction and valence band offsets of CdS/CdTe solar cells fabricated by three different processes have been measured from observations of the variations of open-circuit voltages with temperature. For CdS/CdTe solar cells, the value of the conduction band offsets lies between 0.23 and 0.3 eV, and the value of the valence band offsets lies between 0.67 and 0.74 eV. The method used for the measurement of conduction and valence band offsets is very simple. The values of the saturation current I-o for the different types of cells have been estimated from the slopes of qV(oc) vs KT characteristics and compared with those obtained from lnI vs V curves. The values of I-o found for each cell by these two method are in good agreement.