OBJECTIVE—To project the number of people with diagnosed diabetes in the U.S. through 2050, accounting for changing demography and diabetes prevalence rates.

RESEARCH DESIGN AND METHODS—We combined age-, sex-, and race-specific diagnosed diabetes prevalence rates—predicted from 1980–1998 trends in prevalence data from the National Health Interview Survey—with Bureau of Census population demographic projections. Sensitivity analyses were performed by varying both prevalence rate and population projections.

RESULTS—The number of Americans with diagnosed diabetes is projected to increase 165%, from 11 million in 2000 (prevalence of 4.0%) to 29 million in 2050 (prevalence of 7.2%). The largest percent increase in diagnosed diabetes will be among those aged ≥75 years (+271% in women and +437% in men). The fastest growing ethnic group with diagnosed diabetes is expected to be black males (+363% from 2000–2050), with black females (+217%), white males (+148%), and white females (+107%) following. Of the projected 18 million increase in the number of cases of diabetes in 2050, 37% are due to changes in demographic composition, 27% are due to population growth, and 36% are due to increasing prevalence rates.

CONCLUSIONS—If recent trends in diabetes prevalence rates continue linearly over the next 50 years, future changes in the size and demographic characteristics of the U.S. population will lead to dramatic increases in the number of Americans with diagnosed diabetes.