Due to various linguistic peculiarities, such as unusually long sentences, frequent nominalization, repetitions, binomial expressions, etc., associated with legal language, it is considered a type of LSP, that is, language for special purposes. One of the areas in which the uniqueness of legal language is most clearly manifested is its approach to modality, the grammatical category which determines the relationship between the speaker, what is spoken and extra-linguistic reality. This thesis focuses on the domain of deontic modality, more specifically deontic necessity, a category which encompasses different kinds of obligations that legal provisions impose. As a legal entity encompassing many different cultures and languages, the European Union produces legislation, which has to be translated into all official languages in accordance with the principle of multilingualism. Thus, EU legislation presents an ideal environment for studying different ways in which deontic necessity is translated from English into Croatian. Using both a quantitative and qualitative analysis of the English exponents of deontic necessity and their Croatian translations in two parallel corpora of EU legislation from two different periods (the period prior to the accession of the Republic of Croatia to the EU and the post-accession period), this study aims to uncover the semantic and syntactic regularities associated with different translation choices and to track any potential changes in those patterns in the two periods. By uncovering those patterns the findings of this thesis could contribute to the training of legal translators and thus contribute to the production of more standardized legislation.