The effects of temperature acclimatization on the capacity for rapid cold hardening and supercooling points (SCP) in the Formosan subterranean termite, Coptotermes formosanus, were investigated. The supercooling points (SCP) and mortalities were measured in termites at various exposure time and various constant temperatures or at six selected temperatures when being exposed to decreasing temperatures from 22 oC to -5 oC at a constant rate. The results support the hypothesis that the Formosan subterranean termite has a capacity for rapid cold hardening by changing its supercooling point with increasing periods of temperature acclimation.