There have been many attempts to study and classify ‘false friends’ or ‘false cognates’ so far, but the authors’ aim in this paper is to focus on a particular type, the partial false friends, as the most treacherous ones for several reasons: (1) they share some senses in two given languages and do not coincide in others; (2) they cause far more problems in translations than the totally false friends; (3) they are the product of a complex change of meaning process especially found in the large number of borrowings that English supplies to other languages. To show the importance of getting the right translation, the authors make a selection of Spanish translations of English texts from various sources: literary translations, newspaper and media translations and advertising translations. They find mistranslations that affect the real meaning of the original text in all kinds of literary texts.