EN
The paper discusses the 'Split Morphology Hypothesis' (Perlmutter 1988) and Booij's (1993, 1996) 'Against Split Hypothesis' proposal where inflectional processes feed derivation. In the former part, the authoress discusses criteria of a morphology division: a linear order of morphemes, size of sets of inflectional and derivational markers, a series formation and a degree of grammaticalization of both domains. In the latter part, she presents a theory of inflection and derivation interaction. Booij's inherent and contextual inflection description gives an opportunity to see a contribution of inflectional forms in derivation process. The empirical evidence that supports this hypothesis, also for Polish (Cetnarowska 2001) is given.