Background: Numerous studies have documented racial and ethnic differences in the prevalence and incidence of Alzheimer's disease and related dementias (ADRD). Less is known, however, about racial and ethnic differences in health care expenditures among older adults at risk for ADRD (cognitive deficits without ADRD) or with ADRD. In particular, there is limited evidence that racial and ethnic differences in health care expenditures change over the trajectory of ADRD or differ by types of service.Methods: We examined racial and ethnic patterns and differences in health care expenditures (total health care expenditures, out-of-pocket expenditures, and six service-specific expenditures) among Medicare beneficiaries without cognitive deficits, those with cognitive deficits without ADRD, and those with ADRD. Using the 1996-2017 Medical Expenditure Panel Survey, we performed multivariable regression models to estimate expenditure differences among racial and ethnic groups without cognitive deficits, those with cognitive deficits without ADRD, and those with ADRD. Models accounted for survey weights and adjusted for various demographic, socioeconomic, and health characteristics.Results: Asians and Latinos without cognitive deficits had lower total health care expenditures than whites without cognitive deficits ($10,236, $9,497, $9,597, and $11,541, respectively). There were no racial and ethnic differences in total health care expenditures among those with cognitive deficits without ADRD and those with ADRD. Across all three groups, however, blacks, Asians, and Latinos consistently had lower out-of-pocket expenditures than whites (except for Asians with cognitive deficits without ADRD). Furthermore, service-specific health care expenditures varied by racial and ethnic groups.Conclusions: Our study did not find significant racial and ethnic differences in total health care expenditures among Medicare beneficiaries with cognitive deficits and/or ADRD. However, we documented significant differences in out-of-pocket expenditures and service-specific expenditures. We speculated that the differences may be attributable to racial and ethnic differences in access to care and/or preferences based on family structure and cultural/economic factors. Particularly, heterogeneous patterns of service-specific expenditures by racial and ethnic groups underscore the importance of future research in identifying determinants leading to variations in service-specific expenditures among racial and ethnic groups.