Recent developments in basic research suggest that therapeutic breakthroughs may occur in Alzheimer's disease treatment over the coming decades. To model the potential magnitude and nature of the effect of these advances, historical data from congestive heart failure and Parkinson's disease were used. Projections indicate that therapies which delay disease onset will markedly reduce overall disease prevalence, whereas therapies to treat existing disease will alter the proportion of cases that are mild as opposed to moderate/severe. The public health impact of such changes would likely involve both the amount and type of health services needed. Particularly likely to arise are new forms of outpatient services, such as disease-specific clinics and centers. None of our models predicts less than a threefold rise in the total number of persons with Alzheimer's disease between 2000 and 2050. Therefore, Alzheimer's care is likely to remain a major public health problem during the coming decades.