We present a model for organic bistable devices (OBDs) embedded with metallic nanoparticles. In particular, two device architectures have been studied: a single layer device with metallic nanoparticles dispersed in a organic material matrix and a three layer device where two organic material regions are separated by a layer of heavy packed nanoparticles. The model describes the different behavior, the internal charge and potential distributions in the ON-OFF states. The OFF state is represented by charged nanoparticles forming a space charge layer which limits the current. The ON state occurs with neutral nanoparticles.