The British Universities Human Embryo Database has been created by merging information from the Walmsley Collection of Human Embryos at the School of Biological and Medical Sciences, University of St Andrews and from the Boyd Collection of Human Embryos at the Department of Anatomy, University of Cambridge. The database has been made available electronically on the Internet and World Wide Web browsers can be used to implement interactive access to the information stored in the British Universities Human Embryo Database. The database can, therefore, be accessed and searched from remote sites and specific embryos can be identified in terms of their location, age, developmental stage, plane of section, staining technique, and other parameters. It is intended to add information from other similar collections in the UK as it becomes available.