With the growing interest in cloud computing, more and more businesses are looking not only to migrate their applications to the cloud but also to transform them to better leverage capabilities that are provided by cloud platforms or to enable new business models that are facilitated by the cloud. One problem clients face in this area is a lack of experience and knowledge as to how best to accomplish this transformation. We propose a Cloud Transformation Advisor (CTA) which helps users to select appropriate enablement patterns from a knowledge base of best practices when performing transformation planning. This knowledge base uses a structured representation to capture application information, cloud platform capability information, and enablement pattern information in order to facilitate pattern selection. We describe this representation and a mathematical model which leverages it to choose the "best" combination of patterns for a given transformation problem. We present an example which illustrates the approach, and describe the usage of the CTA. © 2011 IEEE.