This contribution deals with the various verbal morphology in the Italian counterfactual conditionals (the so-called periodo ipotetico dell'irrealtà). Starting from the inventory of all the possible combinations with the imperfetto indicativo that appear in these constructions, it will be shown that the variability of the mood and tense forms is not merely a matter of norm, but that there are clear-cut mechanisms which regulate such variability. Specifically, some peculiar combinations often marked as familiar or, simply, non-standard, are not always possible, but are depending on the actionality of the verbs (telic or atelic) being present in the protasis and/or the apodosis.