Comparison principles for general impulsive stochastic functional differential systems are established. Employing the comparison principles and the theory of differential inequalities, stability and instability, involving two measures, of impulsive stochastic functional differential systems are investigated. Several stability and instability criteria are obtained, and two examples are also given to illustrate our results. Keywords stochastic systems, impulsive functional differential systems, comparison principle, stability in terms of two measures, instability Citation Yao F Q, Deng F Q. Stability of impulsive stochastic functional differential systems in terms of two measures via comparison approach.