The paper describes our research work concerning the pronunciation mode of acronyms in German, French, and Portuguese. Most of the rules are related with the well-formedness of the constituents and the minimum and maximum weight thresholds required for reading and spelling an acronym. The results of the tests for the three languages were considered very promising, reaching decision errors below 4%. The rule set was also applied to a very small English corpus, with relative success. We believe that further optimisation is still possible, if language specific parametrisation is taken into account, in particular for the languages where a limited corpus of acronyms was available.