Word and Paradigm theories of inflection can be classified as inferential-realizational theories, according to the classification of Stump (2001), in that the associations between morphosyntactic properties and exponents of morphology are not listed in the lexicon, but are identified by rules which relate the inflected form with the root, and are selected by their morphosyntactic properties (inferential theories); and morphosyntactic properties are not added to the word by an exponent, but these properties select the exponents that realize them (realizational theories). It has been observed (cf. inter alia Maiden 1992; Pirrelli and Battista 2000) how alternations, on verbal stems that present allomorphy, meet a surprisingly regular distribution, which is not dictated by the phonological context. This regularity reflects the organization of the verbal paradigm, or the set of all inflected forms for each lexeme, into morphomes, purely formal entities independent from morphosyntactic features (Aronoff 1994). In the last twenty years, there has been much interest in studying the paradigmatic distribution of allomorphy, or the way in which variation between forms (the traditional “irregularity”) of a paradigm rests on regular patterns. Practically, these studies aim at analysing the paradigmatic structure of inflection, i.e. to decompose the paradigm into zones where forms are realized on possibly distinct basic stems, and to examine the formal relations (on the phonological level) between these basic stems, looking for predictability chains allowing to handle both regular and irregular lexemes. In the present work, we examine the formal relations between some verbal derivatives in Italian and the basic stems of the related verbs with the goal of extending the study of paradigmatic distribution to derivation. In Latin, verbal derivatives in tionem (event/ result), torem (agent/ instrument), tura (event/ result), tivus (relational adjective), torium (adjective/ instrument/ place) were built on the supine (basic) stem, like the past participle. Italian, as other Romance languages, has inherited from Latin both the process and the derived forms. Some derivatives, and in some cases the past participle itself, underwent semantic drift. Some (ancient) past participles are no longer connected to a verb and remain as independent adjectives (cf. solito ‘usual’). Some past participles of still existing verbs did the same (cf. viso ‘seen’ → ‘sight’ → ‘eyes’ → ‘face’ in modern Italian) while being replaced in their past participle function by analogic forms (visto/veduto ‘seen’). In these cases, derivatives do not display a transparent relation with the past participles of the base verbs. Yet, they maintain formal relations, and these relations allow identifying a basic stem, which is by default identical to the basic stem of the past participle, but can possibly be distinct. This basic stem can be related to other basic stems of the base verb. In particular, we study the relations between the basic stems of verbal derivatives and the basic stems of the related verb, along with a classification of these relations.