The paper describes the twofold experiment aimed at determining the volume and structure of the active vocabulary of the Bulgarian predicatives occurring in dative-predicate constructions. The research and description were based on a technique developed by A. Zimmerling already tested for Russian predicates. The results of the experiment outlined in the paper allow to measure the general volume and frequency of the predicatives occurring in the construction in question and to reveal their distribution into thematic classes. These results may subsequently be used to model the average idiolect and to define the lexical nucleus and the grammatical extension of dative-predicative constructions in Bulgarian.