Purpose: The purpose of this study was to identify relationships between medical, functional, economic, oral health, social, religious, and psychological factors and under-eating in homebound older adults. The focus of the study was on identifying potentially modifiable factors amenable to social and behavioral interventions. Design and Methods: A total of 230 homebound older adults who were currently receiving home health services participated in interviews in their homes using a questionnaire to assess eating behaviors and factors that could possibly affect those eating behaviors. Interviewers measured height and weight, and participants completed three 24-hr dietary recalls. Results: The mean age of participants was 79.1 years. The sample comprised 78% women and 38% African Americans. We found that 70% of participants were under-eating, defined as not consuming enough calories to maintain their current body weight. Participants who were at higher risk of under-eating included men, those receiving either infrequent care or very frequent care by a caregiver, those who had been hospitalized prior to receipt of home health services, and those with a higher body mass index. Implications: Findings from the study have implications for both practice and policy. Experts must develop evidence-based interventions targeted at under-eating in this particularly vulnerable and growing population of homebound older adults. This study provides an initial foundation for the development of targeted evidence-based behavioral nutritional interventions that are noninvasive and cost effective. Copyright 2008 by The Gerontological Society of America.