This paper reports on a specific problem of automatic terminology extraction in Lithuanian – base form inference. While the process of lemmatisation is properly carried out by existing tools, problems arise with normalizing multiword terms. It can be described as the discrepancy between the base form (i. e. lemma) of a term and the sequence of the base forms of constituent lexical items within a term. Lithuanian is a strongly inflected language and the lemmatisation of each word separately within a multiword term breaks the syntactic relations expressed by inflection (case, gender, number) which need to be kept in order to ensure the cohesion of the term.