In this paper, we comment on experiments we have carried out on ceramic perovskites of composition La0.65Ca0.35Ti1-xMnxO3. From low- and high-field magnetic measurements recorded at different temperatures, we have discovered the existence of a large entropic change associated to the ferrimagnetic-paramagnetic transition. Our conclusion is that these materials are excellent candidates as working materials in refrigeration devices. (C) 1999 Published by Elsevier Science B.V. All rights reserved.