A cogrinding process represents a possible strategy to improve the bioavailability of poorly water-soluble drugs because it allows the formation of composite materials (carrier plus drug) where the drug appears in the form of nanocrystals or in an amorphous phase which competes higher water solubility. Because of the fact that many drugs are thermolabile, an accurate knowledge of thermal conditions experienced by a drug during cogrinding is of paramount importance. Accordingly, this paper is focused on the thermal analysis of a vibrational mill by means of a mathematical model representing the mill as a sum of parts where temperature is spatially uniform but changing with time. The only exception is given by the mill bowl where, because of the low heat conductivity and high thickness of its wall, a two-dimensional heat conduction problem is solved. The comparison between the model best fitting and the experimental evidences confirms the reliability of the hypotheses on which the model was built.