Using COSMIC GPS occultation stratospheric temperature and water vapor density data, we examine the tides in the stratosphere. We use a two dimensional spectral analysis method to extract variations in zonal direction in terms of zonal wavenumbers from -5 to 5 and oscillations of time period from a few hours to a few days. At the same time, mesospheric and lower thermospheric (MLT) winds and temperature observed by the TIMED satellite will be analyzed to extract tidal modes in the MLT region. The goal is to examine the propagation of the tides from the stratosphere to the mesosphere. We will investigate inter-annual variations of tides in both the stratosphere and mesosphere to study the QBO effect.