The right to an interpreter is a right that is found in several legislative texts in Spain as well as the rest of Europe. For this reason these documents are examined in teh paper. Secondly, the interpreters' work is analyzed, with special reference made to the provinces of Granada and Málaga. This type of interpreting must be done by professional interpreters who are able to insure that the rights of detainees won't be infringed due to poor interpreting. Interpreters must remain impartial. This is not an easy job and its execution is not limited to a mere knowledge of both the languages involved in the communication. These interpreters must be ready to confront complicated cases.