Apparatus for monitoring the cure of a bone cement material provided in a container includes a memory device in which data is stored relating to the time taken for the cement material of the type in the container to cure according to the temperature of the material. A data processor is used to calculate the time taken for the cement material to cure, based on data relating to the temperature of the cement material and data in the memory device relating to extent of cure. An output device is provided for data from the data processor relating to the extent of cure of the cement material in the container.