Abstract: This paper studies the propagation characteristics of inertial gravity waves in tEe mesosphere using VHF'radar observation data at And.ya(69°N,10°E), Norway June 1987.Several observed examples show quasi-monochromatic wave fluctuations with certain phase progressions.Their periods are several hours,indicating they are inertial gravity waves.The horizontal wave veCtors are estimate.d by analysingthe variations of eastward and northward components of wave-associated fluid velocity.The estimated horizontal wave vectors are typical values observed in mesosphere.Three inertial gravity waves with upward phase progression are also observed.their horizontal wave-associated fluctuation velocities show an anti-clockwise elliptical rotation with increasing lieiglit.The wave-associated fluctuation velocities are 15-40 m/s,illustrating that there exists significant downward wave energy flux.Their kinematical parameters are estimated:period is several hours,vertical phase velocity is from 0.1 to 0.6 m/s,vertical wave length is about 6 km.