Zirconia-based restorations have turned out to be better on account of its high mechanical properties, biocompatibility and aesthetic properties. The negligible marginal fit is the most prominent basis for deciding the clinical success rate. Fracture resistance ought to be surveyed in light of the utilization of the restoration in load bearing regions. Aims and objectives: This in vitro study is aimed to assess the marginal fit, fracture resistance, surface roughness, hardness and phase transformation of yttrium and cerium stabilized zirconia copings with three different occlusal thicknesses and subjecting them to two different aging heat treatment regimens (134º C and 180ºC).