Aim: Aim of the present study was to evaluate the External, Internal and Absolute adaptation of resin composite laminate veneer influenced by preparation design of endodontically treated teeth versus natural tooth. Materials and Methods: Fourteen extracted human maxillary central incisor teeth with similar size and shape will be collected. The teeth will be divided into two equall groups (Group A&B), Group A: natural non endodontically treated tooth with incisal fracture leaving 7 mm and restored with laminate veneer restoration , Group B: natural endodntically treated tooth with incisal facture leaving 7 mm and restored with modified laminate veneer design restoration with (intarcoronalextention). All teeth will be prepared to receive resin composite laminate veneer restoration constructed by indirect technique .The teeth will be teasted for internal ,external and absolute marginal adaptation using stereo microscope with different magnification. Data analysis was performed in several steps. Student t-test was done between both groups. Statistical analysis was performed using Aasistat 7.6 statistics software for Windows (Campina Grande, Paraiba state, Brazil). P values ≤0.05 are considered to be statistically significant in all tests. Results : For external marginal adaptation , the difference of external marginal gap means values between both groups was statistically significant (P<0.05). For internal marginal adaptation, the difference of internal marginal gap means values between both groups was statistically significant (P<0.05).For absolute marginal adaptation, The difference of Absolute marginal gap means values between both groups was statistically non-significant (P>0.05). Conclusion: Machinable resin composite laminate veneer restorations in both designs produced internal adaptation as well as external and absolute marginal adaptation within clinical acceptable range.