Intended for long-term monitoring of the vertical structure and optical properties of clouds and aerosol in bi-polar regions, we are operating Micro-Pulse Lidars (MPLs) at Ny-Aalesund (79N, 12E), Svalbard in the Arctic and at Syowa Station (69S, 40E), Antarctica. These sites are part of the NASA Micro-Pulse Lidar Network (MPLNET). The Arctic MPL measurement started in 1998, and the Antarctic MPL measurement started in 2001. The Geoscience Laser Altimeter System (GLAS) on board the Ice, Cloud and Land Elevation Satellite (ICESat) was successfully launched in January 2003. The lidar observation in a near-polar orbit with an inclination of 94 degrees provides a global coverage of vertical profiles of clouds and aerosol including both polar regions. Data products include thin cloud and aerosol optical depth. GLAS data validation issues include the sensitivity of cloud detection and optical depth accuracy. The polar MPL measurements include GLAS overpasses in 2003 and 2004. ICESat pointed directly to the Ny-Aalesund and Syowa sites when within five degrees off nadir. In this paper, preliminary results from the Arctic and Antarctic MPL measurements will be shown and discussed as ground truth of cloud and aerosol measurements by ICESat/GLAS.