Geographic Information Systems (GIS) technology has advanced significantly over the last ten years, providing a much wider range of approaches to tackle the longstanding challenges of environmental assessments.  Innovative approaches using GIS technology allow improved understanding of the interactions of complex environmental systems from the field to global scale.  Advances in GIS and remote sensing technologies have increased data availability, resolution and quality to a great extent, consequently, expanding what constitutes the “best-available” data to support spatial analyses.  Spatial data development approaches have also provided successful solutions to overcome the limitations in data availability.  For example, value added data layers have been evolved by integration of different data sources and analytics to address specific needs.  This presentation will illustrate current applications of advanced GIS technologies in environmental monitoring and assessment applications by presenting a variety of examples:  data availability pertaining to environmental GIS; integration of remotely sensed data and other spatial data; integration of GIS and modeling (GIS-integrated modeling), analytical frameworks utilizing spatial and statistical modeling approaches, data modeling, spatial data mining and web-based applications.  Uncertainty issues related to spatial analysis involving these geospatial approaches will also be discussed.