The hazards associated with fumigants and other insecticides make it desirable to find a safe alternative for disinfesting artifacts. Freezing is one such possible alternative. It has been used on a very limited basis to disinfest some types of herbarium and archival materials. But some professionals still doubt its efficacy. According to the entomologica literature, the majority of insects are in fact killed by freezing. There are many factors which can influence a particular insect's susceptibility to cold. The most significant variables are temperature and length of exposure. To examine the effects of subfreezing temperatures on one type of museum pest, tests were conducted with Dermestes maculatus Degeer, the hide beetle. Insects were subjected to four subfreezing temperatures, minus 12 degrees C. plus or minus 1.5 degress C., minus 15 degrees C. plus or minus 1.5 degrees C., minus 20 degrees C. plus or minus 1.5 degrees C., and minus 23 degrees C. plus or minus 1.5 degrees C., for exposure periods of 1, 4, 12, 24, 48, 72 and 120 hours. It was found that all stages of Dermestes maculatus could be killed, even when insulted by 5 g. of cotton, by exposures of 48 hours at minus 12 degrees C., 24 hours at minus 15 degrees C., or 4 hours at either minus 20 degrees C. or minus 23 degrees C. All longer exposures also proved fatal. The effect of such exposures on artifacts would be another important consideration in using freezing as a method of disinfestation. Suggestions of ways to assess the effects of freezing on protein materials are provided.