This cross-sectional study included 41 children (age 2 mo-12 y) with pneumonia and 40 healthy controls. Assay of serum copeptin was done using ELISA. Median serum copeptin levels were significantly higher (P=0.03) in children with pneumonia, and in those who died (P=0.04). We conclude that serum copeptin levels seem to be associated with poor outcome in pneumonia.