In order to improve the initial bond strength of a reactive hot melt polyurethane adhesive (RHA), organoclay was added as a modifier. The organoclay caused a viscosity increase as well as a solid-like yield behavior of the RHA in melt state. The enhanced initial and final bond strength and reduced setting time showed that the organoclay improved both the solidification rate after application upon cooling and the bonding interaction. We examined tensile properties and X-ray diffraction patterns of RHAs, and the morphology was observed by transmission electron microscopy.