Membrane damage and reactive oxygen species (ROS) production are multifaceted adverse effects of chilling stress in sensitive fruits and vegetables. They have been attributed to the higher CI tolerance of horticultural products to production and accumulation of heat shock proteins (HSPs), suggesting a central role of HSPs in the acquired tolerance to chilling stress. This beneficial action of HSPs is possible thanks to their chaperone activity. Besides chaperone activity, small HSPs (sHSPs) are able to function as membrane stabilizers and ROS scavengers or to act synergistically with antioxidant system. sHSPs play a key role in maintaining membrane quality attributes such as fluidity and permeability under chilling stress. In fact, the analysis of sHSPs could be envisaged as an ideal method for the assessment of fruits and vegetables¡¯ tolerance to CI and for evaluating the efficiency of postharvest treatments in avoiding CI incidence. This review discusses HSPs and their language of action in mitigation of CI and their potential use as biochemical markers to optimize the use of postharvest treatments. It bridges the division between basic and applied research, and proposes the use of HSPs as biochemical markers of CI.