A recent study established the theoretical basis for a new type of index based on passive microwave vegetation indices (MVIs). The approach was then calibrated for use with data from the Advanced Microwave Scanning Radiometer (AMSR-E) on the Aqua satellite under the assumption that there is no significant polarization dependence of the vegetation emission and attenuation properties. To demonstrate the potential of the new microwave vegetation indices, these were compared with the Normalized Difference of Vegetation Index (NDVI) derived using MODIS at continental and global scales. These results verified that the microwave vegetation indices can provide new and complementary information on vegetation to NDVI for the global monitoring of vegetation and ecosystem properties from space. The next phase of analysis has focused on quantifiable vegetation parameters, specifically vegetation water content that is a valuable parameter in soil moisture retrievals using microwave data. Data sets collected in several recent large scale field campaigns included vegetation water content over domains in addition to conventional indices. Comparisons to date indicate that the MVI does provide vegetation water content information, however, further analysis of vegetation type effects are needed.