Traditionally, languages are assumed to minimally manifest a distinction between nouns and verbs. This assumption has occasionally been debated in the theoretical linguistic literature, in particular in the context of challenging verbal noun constructions that simultaneously manifest nominal and verbal features. From a psycholinguistic perspective, one of the most promising diagnostic criteria for determining whether a given word belongs to the category NOUN or VERB is an event-related brain potential (ERP) component, P200, whose amplitude is larger for verbs than for nouns. So far, a challenge for the interpretation of the P200 has been whether this component reflects verbal (e.g., action) semantics, lexical category or verb-related morphological operation. In the present study we report an ERP experiment whose goal was to contribute to a better understanding of the nature of the “verbal” P200 component by monitoring the comprehension of Polish morphologically related finite verbs, converbs, and verbal nouns. Thereby, we manipulated the syntactic category and morphological complexity of the critical words while keeping their semantics identical. The results show that finite verbs engender a smaller amplitude of the P200 component than less prototypical “verbs” such as verbal nouns and converbs. Based on this observation, we argue that the P200 component reflects the brain activation triggered by the demands of verb-related morphological integration processes performed on the verbal base of derived forms.