The study focuses on the appearance of IGWs downstream of a jet in the upper troposphere on the north-easterly side of an anticyclone over Northern Germany between 17 to 19 December 1999. This wind streak is induced during the poleward Rossby wave breaking event (second phase) north-eastwards of the anticyclone and represents the precondition for the generation of the studied IGWs. 17 radiosonde ascents in an interval of 3 hr and VHF-radar measurements were made from Kuehlungsborn during this period, and are the basis of this investigation. For the studied case of an anticyclone with strong IGWs north-eastwards we found a horizontal wavelength of about 890 km and about 2-3 km in the stratosphere and about 3.3 km in the troposphere for the vertical wavelength. The IGWs are generated downstream of a jet and the phase propagation was upstream with an oscillation rate of about 12.5 hr. The energy propagation was upward in the lower stratosphere and downward in the troposphere. The propagation of the internal IGWs into the middle stratosphere was possible through strong zonal winds over the whole height region due to the position on the edge of the polar vortex. Under the assumption that poleward breaking Rossby waves are often observed in winter we conclude from the above discussed case that IGWs induced by breaking Rossby wave events can contribute essentially to the dynamics of the troposphere and stratosphere.