In this paper, we deal with coreference in Czech complex predicates with light verbs. The syntactic structure of these complex predicates is typically formed by valency complementations of both light verbs and predicative nouns, and its analysis poses a serious challenge for all syntactic theories. We demonstrate that in both deep and surface syntactic structure formation of these predicates, coreference between verbal and nominal valency complementations plays a substantial role. Description of individual types of coreference within complex predicates is thus essential for a comprehensive analysis of their syntactic behavior. In an extensive data annotation project, we identify, delimit and thoroughly describe individual types of coreferential relations between valency complementations of Czech complex predicates.