Background: Barriers to recruiting and retaining acutely ill older adults in clinical research include complexity of illness, fatigue, and early discharge. Objective: To describe recruitment and retention challenges of examining cognitive dysfunction in older adults hospitalized for acute heart failure. Methods: An examination of the reasons for recruitment and retention issues within an acute care, universityaffiliated health care system. Results: Sixty-two patients refused to participate for a variety of reasons; 11 were ineligible, and 27 participants who completed initial data collection refused to participate further because they were too tired, were being discharged on the day of data collection, or were discharged before the next data collection day. Conclusions: Multiple barriers to the recruitment and retention of older adults hospitalized for acute heart failure were identified. Strategies are needed to augment recruitment and retention efforts, including expanding the number of data collection sites and allocating sufficient support resources.