Biocompatible macromer compositions are provided including an isocyanate-functional polyalkylene oxide combined with at least one multi-functional isocyanate as a first component, and a multi-amino functional compound possessing multiple primary amines as a second component. The isocyanate-functional polyalkylene oxide has pendant polyalkylene oxide groups. The resulting biocompatible macromer composition can be employed as an adhesive or sealant for medical/surgical uses.