The stability of couple partnerships is of continual interest to policy makers and many users of official statistics. This research used a sample of adults (from the Office for National Statistics Longitudinal Study) who were in a partnership (married or cohabiting) in the 1991 Census of England and Wales, and then explored whether these individuals were living with the same partner in 2001.Marital partnerships were found to be more stable, even when additional factors were taken into account. Of adults aged 16 to 54, around four in five adults (82 per cent) that were married in 1991 were living with the same partner in 2001. The equivalent figure for adults cohabiting in 1991 was around three in five (61 per cent), of whom around two-thirds (of those remaining with the same partner) had converted their cohabitation to a marriage by 2001. Long-running partnership stability was also found to vary according to the socio-demographic characteristics of individuals and their partners and a summary of these variations is discussed.List of tables, 39.