This article presents the methodology used in a population-based study of early communicative development in Norwegian children using an adaptation of the MacArthur-Bates communicative development inventories (CDI), comprising approximately 6500 children aged between 0 ; 8 and 3 ; 0. To our knowledge, this is the first CDI study collecting data via the Internet. After a short description of the procedures used in adapting the CDI to Norwegian and the selection of participants, we discuss the advantages and potential pitfalls of using web-based forms as a method of data collection. We found that use of web-based forms was far less time-consuming, and therefore also far less expensive than the traditional paper-based forms. The risk of coding errors was virtually eliminated with this method. We conclude that in a society with high access to the Internet, this is a method well worth pursuing.