German cockroaches (Blattella germanica) regularly occurred in a refrigerator of a hospital in Leipzig. Larvae of instars 1--6 of a population of high density but uneven spatial distribution infiltrated through the defective magnetic tape packing of the refrigerator door into an area maintaining +7...12 degrees C. In this way they utilised their temperature dependent ability to move almost down to the lower limit and gave a new example of the plasticity of their reactions. Behavioural and ecological aspects of the observations as well as hygienic consequences and prophylactic measures are discussed.