This report is a study of major problems of translation in the field of psychology. It is based on a definition of translation as the attempt by a translator to communicate in a target language most or part of the meaning of a source-language (ST) text to a particular target-language-readership. The problems resulting from each point of this definition are analysed and illustrated with the help of material taken from books and Journals of Psychology or Psychoanalasis in English, French or German. The problems analysed range from the view of translation as tentative, to a view of translation as a semantic exercise involving the careful decoding and re-encoding of each layer of the ST i.e. lexical, morphological, phonological, syntactic, structural and stylistic. Each of these layers gives rise in turn to a number of problems such as synonymy, polysemy,ambiguity, neologisms, syntactic "faux amis", structuralinterference etc... Two practical problems are also mentioned : the translator''s tools and the time factor. In conclusion, the skills needed by the translator are listed, and the main points are summarized.