In this paper, I offer a morphological account of the mixed paradigms in Italo-Romance, i.e. the cases where there is, in compound tenses, auxiliary alternation between ESSE and HABERE (henceforth E/H) within one and the same (sub)paradigm. I intend to show that in such paradigms auxiliary selection traditionally following the split intransitivity criterion, becomes morphologized. Consequently, the intraparadigmatic auxiliary alternations attested in a wide range of Italo-Romance varieties (cf. Loporcaro 2001; 2007; 2014; Manzini & Savoia 2005, among others) can follow various morphological patterns, ranging from morphosyntactically coherent (motivated) to those which do not seem to form a natural class (i.e., those traditionally termed 'morphomic'). I take the intraparadigmatic auxiliary alternation as a phenomenon which induces a split within periphrasis (cf. Corbett 2013; 2015a; 2015b), assuming, at the same time, the perfective auxiliary constructions to be clear instances of inflectional periphrasis (along the lines of Ackerman & Stump 2004; Brown et al. 2012). Such an assumption leads to the question recently put forward by Vincent (2011: 434)-"if periphrases can become part of a paradigm, can they exhibit the distributional behaviour associated with autonomous morphomes?-and follows also some of the recent attempts to deal with the periphrasis in morphomic terms (cf. Cruschina 2013; Ledgeway forthcoming). As is well known, in standard Romance languages, compound tenses can exhibit one generalized auxiliary or they can present auxiliary selection on the basis of the active/stative split. However, this clear-cut situation where, on the one hand, one perfective auxiliary is generalized, and, on the other hand, auxiliary selection follows the split intransitivity criterion, is far from being the only pattern of alternation attested in the Romance languages (