In order to describe non-systemic valency behavior of Czech deverbal nouns, we present results of an automatic comparison of valency frames of interlinked noun and verbal lexical units included in valency lexicons NomVallex and VALLEX. We show that the non-systemic valency behavior of the nouns is mostly manifested by non-systemic forms of their actants, while changes in the number or type of adnominal actants are negligible as for their frequency. Non-systemic forms considerably contribute to a general increase in the number of forms in valency frames of nouns compared to the number of forms in valency frames of their base verbs. The non-systemic forms are more frequent in valency frames of non-productively derived nouns than in valency frames of productively derived ones.