The invention relates to a device for the temperature monitoring of a cryopreserved biological sample, comprising a sample container having an accommodating space (2) for accommodating the sample and comprising an indicating apparatus, which can be arranged on the outside of the sample container, for monitoring at least one temperature limit value. The indicating apparatus has at least one cavity, which is only partially filled with an indicating substance, the melting temperature of which lies in a range from -20 °C to -140 °C. The indicating apparatus can be designed, in particular, as a cylindrical body, which can be fastened to a cryotube as a bottom part, or alternatively as a double-walled hollow cylinder, which can be slid onto an outer lateral surface of the cryotube. The indicating apparatus can also be fastened to a lateral outer wall of the sample container, e.g. as a hollow body that can be inserted into a sleeve or insertion pocket.