The magnitude 9.0 earthquake centered off the west coast of northern Sumatra (3.307¿N, 95.947¿E) on December 26, 2004 at 00:59 UTC (United States Geological Survey (USGS) (2005), USGS Earthquake Hazards Program-Latest Earthquakes, Earthquake Hazards Program, http://earthquake.usgs.gov/eqinthenews/2004/usslav/, 2005) generated a series of tsunami waves that devastated coastal areas throughout the Indian Ocean. Tide gauges operated on behalf of national and international organizations recorded the wave form at a number of island and continental locations. This report summarizes the tide gauge observations of the tsunami in the Indian Ocean (available as of January 2005) and provides a recommendation for the use of the basin-wide tide gauge network for future warnings.