Objective: It is generally thought that causes of undernutrition are multifactorial, but there are limited quantitative studies performed. We therefore examined a wide range of potential factors associated with undernutrition in communitydwelling older adults. Design: Cross-sectional study. Setting: Community-dwelling older adults (>= 65 years) receiving home care in the Netherlands. Subjects: Data on potential factors associated with (risk of) undernutrition were collected among 300 older adults. Nutritional status was assessed by the SNAQ(65+) instrument. Undernutrition was defined as mid-upper arm circumference <25 cm or unintentional weight loss of >= 4 kg in 6 months. Being at risk of undernutrition was defined as having poor appetite and inability to walk up and down stairs of fifteen steps, without resting. Results: Of all participants, ninety-two (31.7%) were undernourished and twentyfour (8.0%) were at risk of undernutrition. Based on multivariate logistic regression analyses, the statistically significant factors associated with (risk of) undernutrition (P <0.05) were: unable to go outside (OR=5.39), intestinal problems (OR=2.88), smoking (OR =2.56), osteoporosis (OR=2.46), eating fewer than three snacks daily (OR=2.61), dependency in activities of daily living (OR=1.21), physical inactivity (OR=2.01), nausea (OR=2.50) and cancer (OR=2.84); a borderline significant factor was depression symptoms (OR =1.83, P=0.053). Conclusions: The study suggests that (risk of) undernutrition is a multifactorial problem and that associated factors can be found in several domains. These findings may support the development of intervention trials for the prevention and treatment of undernutrition in community-dwelling older adults.