The objective of this paper is to examine the deformation behavior and water tightness of clay-based composite cover of landfills subjected to differential settlements using a centrifuge modeling technique. A short series of centrifuge tests were performed at 40 gravities on model composite cover system formed using a model clay barrier of 15mm (0.6m) thickness, geomembrane and overburden equivalent to that of landfill covers. The effect of presence of overlaps within the geomembrane layers at the zone of maximum curvature was also investigated. Centrifuge model test results on cover system formed with a 15mm (0.6m) thick clay barrier experienced water breakthrough once limiting distortion level is equal to 0.056. In comparison, a composite cover system formed with a 15mm (0.6m) thick clay barrier and a geomembrane was found to sustain large distortions without any water breakthrough even after subjecting to a maximum distortion level of 0.125. However, with the presence of overlaps at the zone of maximum curvature, the sealing efficiency of the composite cover with 15mm (0.6m) thick clay barrier was observed to decrease and limiting distortion level was 0.10. An attempt was also made to model the deformation behavior of barriers with and without geomembrane by finite element analysis using Plaxis 2D software. © 2012 American Society of Civil Engineers.