It is generally assumed that grammaticalization is a major process in linguistic change (Lehmann 1985, Marchello-Nizia 2006). It is also assumed that grammaticalization does not affect homogeneously all linguistic categories (Hopper & Traugott 2003), or even all languages: it has been said, for instance, that some languages are further down most grammaticalization clines than others and, thus, appear more grammaticalized than others (see, for French. In this paper, we illustrate the uneven pace of grammaticalization in Romance by analysing a specific area of language, viz. simple and complex prepositions. Our goal is to establish a list of prepositions which are in actual use in five present-day Romance languages (to wit, French, Italian, Portuguese, Romanian and Spanish). In order to do so, we check the validity of existing lists against written and spoken corpora, and evaluate the degree of grammaticalization of each morpheme or construction, on the basis of (mainly) morpho-syntactic criteria. Additionally, and most importantly, a corpus-based approach makes it possible to observe these items' frequency (Bybee 2006). The result offers a clear picture of the degree of grammaticalization of prepositions in present-day Romance, showing that French seems indeed to be the most grammaticalized Romance language, followed by Italian, Spanish, Portuguese and Romanian.