In recent years it has become increasingly clear that stochasticity plays an 
important role in many biological processes. Examples include bistable genetic switches, 
noise enhanced robustness of oscillations, and fluctuation enhanced sensitivity or “stochastic 
focusing". Numerous cellular systems rely on spatial stochastic noise for robust performance. 
We examine the need for stochastic models, report on the state of the art of algorithms and 
software for modeling and simulation of stochastic biochemical systems, and identify some 
computational challenges.
