We report measurements of the low‐frequency optical response in epitaxial thin films of La0.67Ca0.33MnO3in the temperature range covering both the ferromagnetic metallic state and the paramagnetic insulating state. We observe a bolometric optical response in fully oxygenated films of the above composition as well as in oxygen deficient films. In both types of samples, the optical response is thermal in nature as indicated by its proportionality with the temperature derivative of the resistancedR/dT. ©1996 American Institute of Physics.