This work presents an ultra-low-power, biologically inspired pseudo-random number generator based on the Hodgkin-Huxley silicon neuron circuit. The chaotic phenomenon observed in neurons is exploited to generate random numbers. The random sequence generated by the proposed system passed the statistical tests specified by Federal Information Processing Standard. The proposed random number generator circuit provides an ultra-low-power alternative for pseudo-random number generation with 180nW power consumption. © IEICE 2012.