The concept of pattern, meant as an interesting knowledge artifact extracted from data, is considered to be a an effective answer to the advanced analysis requirements emerging in complex industrial and scientific applications. Overall, it appears that designing and building large pattern-bases will probably be a hot issue for future applications. In this paper we focus on conceptual design of pattern-bases, by discussing how UML could be used and extended to this end. In particular we address the main issues in static modeling, including the representation of relationships between patterns, and we briefly present some issues related to functional and dynamic modeling.