This study re-evaluates the representation of phonological length in Finnish in the light of Optimality Theory. The Obligatory Contour Principle (OCP) prohibits sequences of identical elements. It follows that long segments cannot be represented as sequences of two short segments, but must be interpreted monosegmentally (i.e. non-linearly). In Finnish, long segments have been traditionally represented bisegmentally, consequently violating the OCP. There are, however, phenomena in Finnish, such as dialectal epenthesis, which pattern long consonants with short ones rather than with bisegmental consonant clusters. This study provides an Optimality Theoretic analysis for dialectal epenthesis, and shows that the analysis predicts that monosegmental representation is the optimal way of representing long consonants in Finnish as well.