This paper describes the development of Finnish linguistic resources for use in MedSLT, an Open Source medical domain speech-to-speech translation system. The paper describes the collection of medical Finnish corpora, the creation of a Finnish grammar by adapting the original English grammar, the composition of a domain specific Finnish lexicon and the definition of interlingua to Finnish mapping rules for multilingual translation. It is shown that Finnish can be effectively introduced into the existing MedSLT framework and that despite the differences between English and Finnish, the Finnish grammar can be created by manual adaptation from the original English grammar. Regarding further development, the initial evaluation results of English-Finnish speech-to-speech translation are encouraging.