This article is partly based on a newly published influenza pandemic preparedness plan and risk analysis for future pandemics in Norway, and presents estimates on morbidity and mortality in influenza pandemics in Norway in the 20th century. In addition, estimates on morbidity and mortality for a future pandemic are given. One of the main conclusions is that excess mortality in connection with Spanish influenza and Asian influenza is highly underestimated. The proportion of the infected that died in the pandemics was low, and was highest for Spanish influenza. The morbidity will be highest if a pandemic similar to Asian influenza reappears, while mortality will be highest if a Spanish flu is repeated. In the worst case scenario for a pandemic today, based on the figures from the Spanish flu, the number of excess deaths could reach 29,000, an increase of 60% compared to the average annual number of deaths seen in the 1990s.