With a computerized data base, a data retrieval system, and a computer program using the actuarial method of life-table analysis, we compared survival rates in different subgroups of patients with dementia of the Alzheimer type (DAT; n = 199). Men (n = 71) had a shorter duration of survival than women (n = 128), with 500-day survival (mean +/- SEM) 84 +/- 5% vs. 99 +/- 3%, p less than 0.01; 1000-day survival 49 +/- 10% vs. 96 +/- 8%, p less than 0.001; 50% survival 1000 days vs. 1550 days. Patients younger than 65 years at onset had a decreased relative duration of survival compared with patients over 65 at onset, suggesting a more malignant course. Patients with a longer duration of illness tended to die sooner, but this effect was not statistically significant. The Kahn-Goldfarb mental-status quotient was not a predictor of survival. Patients with high Haycox behavioral score (greater than 20; n = 50), indicating more severe behavioral impairment, had lower survival rates at 500 days than patients with low scores (less than 12; n = 65) (80 +/- 6% vs. 95 +/- 3%, p less than 0.05). Hachinski ischemic score, measuring signs and symptoms of vascular disease, had no correlation with survival. Factors associated with decreased duration of survival in DAT include male sex, presenile onset, and increased severity of behavioral impairment.