This article argues against the hypothesis that roots are stored in the lexicon without categorial specification, such as noun and verb, as proposed in Marantz (1997, 2001). On the basis of evidence from Dutch, we show that certain generalizations and rules cannot be expressed without having roots that are lexically specified for their category. Furthermore, we show that the arguments put forward by Barner and Bale (2002) for categorial underspecification are not valid with respect to the data from Dutch. Finally, following Kiparsky (1997), we show that analyses of denominal verbs in English that embrace the categorial underspecification hypothesis run into serious problems. We conclude that roots are stored in the lexicon with a categorial specification.