The energy distribution profile of the interface states (N-ss) of Al/TiO2/p-Si (MIS) structures prepared using the sol-gel method was obtained from the forward bias current-voltage (I-V) characteristics by taking into account both the bias dependence of the effective barrier height (phi(e)) and series resistance (R-s) at room temperature. The main electrical parameters of the MIS structure such as ideality factor (n), zero-bias barrier height (phi(b0)) and average series resistance values were found to be 1.69, 0.519 eV and 659 Omega, respectively. This high value of n was attributed to the presence of an interfacial insulator layer at the Al/p-Si interface and the density of interface states (N-ss) localized at the Si/TiO2 interface. The values of N-ss localized at the Si/TiO2 interface were found with and without the R-s at 0.25-E-nu in the range between 8.4 x 10(13) and 4.9 x 10(13) eV(-1) cm(-2). In addition, the frequency dependence of capacitance-voltage (C-V) and conductance-voltage (G/omega-V) characteristics of the structures have been investigated by taking into account the effect of N and R, at room temperature. It can be found out that the measured C and G/omega are strongly dependent on bias voltage and frequency. (C) 2010 Elsevier B.V. All rights reserved.