A multicentre cohort of 513 clinic attenders with systemic lupus erythematosus (SLE) was retrospectively identified, representing 4185 patient-years of follow-up. Expected numbers of death were calculated by means of age- and sex-specific mortality rates of the general Danish population. The observed number of deaths was 122. The survival rates were 97%, 91%, 76%, 64% and 53% after 1, 5, 10, 15, and 20 years respectively. The overall mortality rate was 2.9% per year (95% CI 2.4-3.5), and the standardized mortality rate (SMR) was 4.6 (95% CI 3.8-5.5). The causes of death included active SLE (n = 19), end stage organ failure due to SLE (n = 16), infections (n = 25), malignancy (n = 9), cardiovascular disease (n = 32), and other causes (n = 21). SLE was directly related to one third of the excess mortality. In conclusion, SLE patients in the present cohort had a 4.6-fold increased mortality compared with the general population and half of the deaths were caused by SLE manifestations or infections, especially in young patients during the early period of the disease.