The World Ocean Circulation Experiment (WOCE) sea level data set comprises data collected from approximately 160 tide gauge sites distributed around the world. The data are usually hourly heights of sea surface elevation, although some were collected and supplied at higher frequencies (i.e. 6 or 15 minute intervals) or as pressure values rather than elevations. The data are primarily from 1990 to 1998 (the WOCE period), but the dataset also includes historical data as a number of the tide gauges had been operating for many years. The total volume of data held is 3550 site years. A few sites have data extending back over 50 years and many over 20 years. The British Oceanographic Data Centre (BODC) was responsible, as a WOCE Data Assembly Centre (DAC), for assembling, quality controlling and disseminating this comprehensive sea level data set. Data were supplied by Argentina, Australia, Canada, Chile, China, Cuba, Denmark, Ecuador, France, Iceland, Japan, New Zealand, Peru, Philippines, Portugal, Russia, South Africa, Spain, Ukraine, the UK and the USA. Data quality control was carried out with the aid of sophisticated screening software which allows rapid inspection of the data. The sea level data were tidally analyzed and the residuals inspected. Parameters other than sea level, for example atmospheric pressure and sea surface temperature, were also visually inspected. This quality control identified spikes and gaps in the data in addition to timing problems and datum shifts. Any problems identified were resolved with the data supplier. Qualifying information accompanying the data was also checked and data documentation assembled. The data can be downloaded from the BODC web site, or made available on CD-ROM.