Reaching the patient satisfaction through superior esthetic is one of our main aims as dental practitioners. Technology development of the ceramic materials together with the adhesive cements results in conservative restorations with superior bond values. The purpose of the current study was to evaluate the shear bond strength of Vita Enamic blocks to enamel and dentine substrate utilizing Bifix QM resin cement versus the Rely X Ultimate Clicker. Twenty eight freshly extracted human premolars teeth free of decay or fracture were selected for this study. The enamel samples were prepared by flattening enamel only from the buccal surface of each tooth. The dentin samples were prepared by flattening of the buccal surface of each tooth till dentin surface was exposed. For shear bond strength testing, the teeth were divided into two main groups according to the resin cement used:Group (A): 14 disc samples cemented with Bifix QM resin cementGroup (B): 14 disc samples cemented with Rely X Ultimate Clicker. Each group was further subdivided into two subgroups according to the type of the dental substrate utilized for bonding; either enamel or dentin. Subgroup (1): includes 7discs samples bonded to enamel. Subgroup (2): includes 7discs samples bonded to dentin. Following cementation of all samples, all specimens were stored in distilled water for 24h at 37℃, and then they were exposed to aging thermocycling (500cycles, ± 5°C/55°C). The cemented assembly was then transferred to the Instron universal testing machine for shear bond strength determination. Examination of the debonded surfaces of the samples was performed by digital microscope to evaluate the mode of failure. For statistical analysis student t-test was used between main groups with dental substrate. Two way ANOVA test was used between cement groups and substrate subgroups. Results of shear bond strength showed the following:1-Within enamel it was found that Rely X Ultimate group showed statistically higher mean ± SD value of shear bond strength than Bifix QM group.2-Within dentin it was found that Bifix QM group showed statistically non significant higher mean ± SD value of shear bond strength than Rely X Ultimate group.