We have studied the resistivity and thermoelectric power of Pr 0.66R0.04Sr0.3MnO3 where R = Tb, Y, Ho and Er and have analyzed it within a percolative framework. Both resistivity and thermoelectric power quantities were found to show a strong dependence on the disorder (〈CT〉") with the high temperature activation energy in both increasing as 〈σ〉2 is increased, implying that as the disorder increases, carriers get more localized. The percolative nature of the thermopower was analyzed assuming that the lattice has coexisting metallic (Smet) and insulating (Sins) components above and below the Curie temperature (TC) which are independent of each other. Hence total S(T) = pSmet(T) + (1-p)Sins with the volume metallic fraction p=1/(1+exp(-Uo(1-T/TC)/k BT) [1]. A similar analysis was done using the resistivity data. It was seen that the TC from both thermopower and resistivity fits were nearly the same indicating that they have a common origin. This analysis clearly proves that the metal insulator transition in manganites is percolative in nature and that the transport properties show a strong percolation tendency. © 2005 Materials Research Society.