The paper is focussed on the preliminary results of a program of full scale tests of geosynthetic reinforced retaining walls carried out by the Geotechnical Research Group at the Royal Military College of Canada (RMCC). The long term research program involves the construction of 10 walls. The paper describes the test program, some instrumentation details and presents selected results from the first four walls completed to date. Three of the walls were constructed with a column of dry-stacked modular concrete units and one nominal identical wall was constructed with a wrapped-face. All of the structures were surcharge loaded to stress levels well in excess of working load conditions. The data gathered from this program has been useful to identify important performance features of the reinforced soil structures and to identify possible sources of conservatism in current methods of analysis for geosynthetic reinforced soil structures in North America. The high quality data will also prove useful for calibration of numerical models