There is a belief among professional translators, translation theorists and even those involved in teaching translation that translation theory is of little use, if any at all, in the training of specialised translators. Such beliefs are usually based on the assumption that teaching the craft to aspiring specialised translators should be restricted to such aspects as the study of specialised language characteristics in general as well as in relation to areas of specialism, the study of terminology and the translation of specialised texts. The present paper strongly disagrees with such views and will attempt to explain the reasons by (a) proving the crucial role played by translation theory in training specialised translators and explaining why and (b) showing at what stage and how such knowledge becomes necessary in the training of specialised translators. The conclusions reached by the paper will be mainly based on the writer's own experience in teaching translation to specialised translators.