Non-finito is a term used to identify an artwork as unfinished, while referring to the visibility of the medium in which it was (being) made. A work can be left unfinished either as a result of historical coincidence, or by its author’s intention, where non-finito is used as a pictorial principle, which puts it in a complex relation with different mimetic theories. While the previous explorations of these themes focused separately on each phenomenon, this work explores the nature of their relation, regarding the theory and practice of mainly 16th and 17th century painting. Considering the complexity of both non-finito and mimesis, whose definition depends on the way in which a certain culture, period, region, author, or work perceive reality, it is not always simple to unequivocally determine whether they are contradictory or complementary. However, in general terms, if mimesis is considered a total illusion where the difference between art and reality is unnoticeable, non-finito is then anti-mimetic, as it disrupts the clarity of said illusion. On the other hand, it offers painters a method of creating pictures even more seemingly real than those conventionally finished, alluding and suggesting, rather than describing their subjects, which enables them to express more complex meanings rooted equally in form as in the content of the work.