The Centre for Longitudinal Studies, which is responsible for the UK Millennium Birth Cohort Study, and the British birth cohorts of 1958 and 1970, is organising an international conference at St Catherine's College, Oxford, from 12 to 14 September 2006. The conference will focus on the international experience of large-scale birth cohort studies which were started around the turn of the new millennium, i.e. studies whose subjects were born within a decade either side of 2000, and who have so far only been observed as children. The object of the conference is to promote communication and comparison between those designing, conducting and analysing such surveys in different countries.