Abstract—Sensitivity methods have been originally developed for analysis of technical systems. Recently these methods have gained increasing importance in the analysis of biological systems. Among others, they allow to rank parameters of mathematical model describing complex biological system, according to their influence on system behavior. These parameters represent biochemical processes crucial for a given biological system and their modification (e.g. by using pharmacological agents) may prove beneficial in the treatment of many diseases. In this work, we propose a novel method of sensitivity analysis based on the frequency distribution of a model transient response. The method may be used to find potential molecular targets for new drugs and takes into account the heterogeneity of cell population with respect to their responses to a drug agent.