The subject of this thesis is the use of the cleft construction in English and Norwegian. These languages employ a formally similar construction to focus a sentence element, but the use of the construction is not always identical. The analysis is carried out on English and Norwegian translations of Czech texts. The main aim of this thesis is to identify and analyse possible types of motivation for the use of the cleft construction. The studied types of motivation are the FSP, textual and syntactic motivation. The analysis of the FSP motivation is based on the theory of the FSP as described by Jan Firbas (Firbas 1992). The list of textual functions is based on the work of Jan Firbas (Firbas 1995) and Hilde Hasselgard (Hasselgard 2004). Some types of the syntactic motivation are proposed by Libuše Dušková (Dušková 1999: 319), but the types described in this thesis result from the present analysis. In addition to the motivation for the use of the construction, the thesis deals with Norwegian and English counterparts of the analysed cleft sentences. These counterparts are divided into three groups: the cleft or pseudo-cleft construction, the underlying non-cleft construction and a different construction (cf. chapter 4.4.). The purpose of the analysis is to find where the use of the cleft construction differs in English and Norwegian. The results may be useful for language learning and translation because the use of the cleft construction is very similar in English and Norwegian and this sometimes leads to linguistic interference.