A changing climate is increasing the frequency, intensity, duration and spatial extent of heat waves. These changes are associated with increased human mortality during heat extremes. At the other end of the temperature scale, it has been widely speculated that cold-related mortality could decrease in a warmer world. We aim to answer a key question; the extent to which mortality due to temperature extremes in Stockholm, Sweden during 1980–2009 can be attributed to climate change that has occurred since our reference period (1900–1929).