Dependence of the trap density and the distribution on the current bistability in organic bistable devices (OBDs) was investigated by using the space charge limited current (SCLC) model. The single level trap and the Gaussian trap distributions of the SCLC model were used to clarify the electrical bistability of two states with different conductivities. The electrical bistability of the modified SCLC model consisting of two Gaussian distributions with different trap depths provided more accurate results in comparison with that of different models. The calculation results of the current density-voltage characteristics for the OBDs taking into account the parallel resistor were in reasonable agreement with the experimental results. (C) 2011 Elsevier B. V. All rights reserved.