Protein Energy Malnutrition is associated with numerous poor health outcomes, including high health care costs, mortality rates and poor physical functioning in older adults. This systematic literature review aims to identify and provide an evidence based overview of potential determinants of protein-energy malnutrition in community dwelling older adults. A systematic search was conducted in PUBMED, EMBASE, CINAHL and COCHRANE from the earliest possible date through January 2013. Observational studies that examined determinants of protein-energy malnutrition were selected and a best evidence synthesis was performed to summarize the results. In total 28 studies were included in this review from which 122 unique potential determinants were derived. Thirty-seven determinants were examined in sufficient number of studies and were included in a best evidence synthesis. The best evidence score comprised design (cross-sectional, longitudinal) and quality of the study (high, moderate) to grade the evidence level. Strong evidence for an association with protein-energy malnutrition was found for poor appetite, and moderate evidence for edentulousness, having no diabetes, hospitalization and poor self-reported health. Strong evidence for no association was found for anxiety, chewing difficulty, few friends, living alone, feeling lonely, death of spouse, high number of diseases, heart failure and coronary failure, stroke (CVA) and the use of anti-inflammatory medications. This review shows that protein-energy malnutrition is a multi-factorial problem and that different domains likely play a role in the pathway of developing protein-energy malnutrition. These results provide important knowledge for the development of targeted, multifactorial interventions that aim to prevent the development of protein-energy malnutrition in community dwelling older adults.