This article describes the conversion of the British Household Panel Survey (BHPS) to a computer aided personal interviewing (CAPI) mode of data collection. The BHPS is a panel survey, now in its 10th year of data collection, carried out by the Institute for Social and Economic Research based at the University of Essex. Moving to CAPI midway in the life of a panel survey presents particular challenges, and the article discusses the implications of the move and details the staged strategy by which it was accomplished within a very tight timescale. The authors show how this approach has provided many of the benefits of a CAPI mode of data collection while posing little risk to the integrity of the panel sample as a whole, generating, nevertheless, challenges of its own.