The article is devoted to the analysis of discursive specifity of mental verbs in the deontic utterance in two types of institutional discourse in German — scientific and political, which regulate social relations of a certain type, differing in its object. It describes its differences in basic discursive parameters (goal, addressee, forms of persuasion, temporal organization, expressed norms), which determine the specifics of the deontic utterance and its usage. It establishes the quantitative representation of deontic utterances in scientific and political discourse, as well as the quantitative representation of certain types of semantic verbs (behavioral, communicative, mental) in deontic constructions, which is determined by the peculiarities of each social practice. The study identified the set of mental verbs in deontic structures in the studied types of institutional discourse. The discursive set of mental verbs is determined by the subject areas of the social practice, served by scientific and political discourse. It reveals the aspects of mental activity brought into the focus of the deontic modality; it determines the dominance of certain lexical-semantic groups of mental verbs in scientific and political discourse. The research evolves the type of the deontic subject of modal utterances with mental verbs — the generalized subject: it has an indefinite referential scope in scientific discourse; it is an inclusive “we”-subject in political discourse. It finds out the pragmasemantic characteristics of deontic constructions with mental verbs in two discourses that differ in pragmatic goals. It is noted that it is quite difficult in scientific discourse to differentiate distinctly the illocutionary characteristics (directiveness or representativeness) of the deontic utterance with a mental verb due to the uncertainty of the referential scope of the deontic subject. Modal utterances with mental verbs realize in political discourse either directive illocution, implying a call for joint action, or interrogative illocution. The research establishes the semantic diffuseness of mental verbs in the deontic utterance in political discourse; it detects their semantic enrichment determined by the subject area of political discourse.