XML is increasingly gaining acceptance as a medium for exchanging data between applications. Given its text-based structure, XML can easily be distributed across any type of communication channel, including the Internet. This article provides an overview of an efficient way to store XML data inside an object-oriented database management system (OODBMS). It first discusses the difference between XML data and XML documents, and then introduces an approach to integrate XML data into the Java/sup TM/ programming language and programming model. This integration is combined with the transparent persistence of Java objects defined by the ODMG.