Data is often populated into Configuration Management Databases (CMDBs) from different sources. Because the data can come from a variety of sources, it may have inconsistencies—and may even be incomplete. A Normalization Engine (NE) may be able to automatically clean up the incoming data based on certain rules and knowledge. In one embodiment, the NE takes each Configuration Item (CI) or group of CIs that are to be normalized and applies a rule or a set of rules to see if the data may be cleaned up, and, if so, updates the CI or group of CIs accordingly. In particular, one embodiment may allow for the CI's data to be normalized by doing a look up against a Product Catalog and/or an Alias Catalog. In another embodiment, the NE architecture could be fully extensible, allowing for the creation of custom, rules-based plug-ins by users and/or third parties.