Protein-energy malnutrition (PEM) is highly prevalent among peritoneal dialysis (PD) patients and is a strong predictor of morbidity and mortality. A wide range of factors can lead to PEM and associated wasting (PEM/W) in PD patients, but persistent inflammation and the presence of diabetes have been identified as the two main reasons. An important body of literature has been reporting studies of methods suitable for detecting malnutrition in its early phase so that appropriate intervention can be provided. Although assessment of nutrition status has been substantially improved, no definitive single method of assessing nutrition status has been decided. Rather, several different markers of nutrition should be evaluated together. Because of the complexity of treating malnutrition in PD patients, nontraditional strategies such as appetite stimulants, anti-inflammatory diets, and anti-inflammatory pharmacologic agents are recommended to be combined with more traditional forms of nutritional support, so as to provide a better chance of recovery. The present review briefly discusses the causes of PEM/W, the methods most commonly used to identify the condition, and the new management strategies available.