OBJECTIVES: To investigate mortality among users of hostels for homeless people in Copenhagen, and to identify predictors of death such as conditions during upbringing, mental illness, and misuse of alcohol and drugs. DESIGN: Register based follow up study. SETTING: Two hostels for homeless people in Copenhagen, Denmark PARTICIPANTS: 579 people who stayed in one hostel in Copenhagen in 1991, and a representative sample of 185 people who stayed in the original hostel and one other in Copenhagen. MAIN OUTCOME MEASURE: Cause specific mortality. RESULTS: The age and sex standardised mortality ratio for both sexes was 3.8 (95% confidence interval 3.5 to 4.1); 2.8 (2.6 to 3.1) for men and 5.6 (4.3 to 6.9) for women. The age and sex standardised mortality ratio for suicide for both sexes was 6.0 (3.9 to 8.1), for death from natural causes 2.6 (2.3 to 2.9), for unintentional injuries 14.6 (11.4 to 17.8), and for unknown cause of death 62.9 (52.7 to 73.2). Mortality was comparatively higher in the younger age groups. It was also significantly higher among homeless people who had stayed in a hostel more than once and stayed fewer than 11 days, compared with the rest of the study group. Risk factors for early death were premature death of the father and misuse of alcohol and sedatives. CONCLUSION: Homeless people staying in hostels, particularly young women, are more likely to die early than the general population. Other predictors of early death include adverse experiences in childhood, such as death of the father, and misuse of alcohol and sedatives.