The aim of the study is to evaluate and compare the marginal fit and internal adaptation of endocrowns with various preparation depths 3 mm, 5 mm, and 7 mm fabricated using conventional and optical impression. 3 mandibular molar root canal models were taken and endodontically treated. Each of them was prepared with different intracoronal depths 3 mm, 5 mm, and 7 mm to receive endocrowns. Conventional putty wash impression was taken for each tooth and die was poured. They were subjected to intra oral scanning and virtual models were produced. The crowns were designed in Dental CAD software and milled using zirconia blanks with a cement space of 70 μm. Fit checker was placed between the milled crowns and their corresponding models. Silicone replica technique was used to visualize the fit checker. The sections were scanned and widths of each wall were measured using a digital microscope. Within the limitations of the study we may conclude that in the presence of a standardized digital intraoral scanner a digital impression that is more accurate than a conventional wash impression can be made up to an intracoronal depth of 7 mm. Intracoronal preparation depth do not seem to affect the marginal fit or internal adaptation of an endocrown whether the impressions are made digitally or using traditional silicone wash impression method.