The work addressed to the study of the Roman mortars used in the construction of the Maritime Theater of Villa Adriana, located in Tivoli (Rome), dating to the II sec. A.D. and UNESCO Cultural Heritage since 1999. By mineralogical-petrographic, XRPD, SEM-EDS and physical analysis, the granulometric composition and distribution of the aggregate, type and characteristics of the binder, and various physical-mechanical properties of mortars (density, porosity, water absorption, imbibition and saturation indexes, mechanical resistance) were defined. In addition, through thin section digital image analysis, the binder / aggregate ratio and some geometric characteristics of the aggregates (e.g. circularity) were determined. The value of the binder / aggregate ratio has been very useful in defining the compositional standards in relation to the function of the mortars in the analysed building, the technical quality of the mortar production and any inomogeneities resulting from the production processes or from the construction phases of the building. The layers (arriccio and intonachino) of some plasters used in the interior wall of the porch and some bedding mortars of the truncated-pyramidal bricks (i.e. cubilia) of the circular bearing masonry have been studied in particular. In addition, the petrographic characteristics of cubilia bricks made with acid volcanic rocks have been studied, aiming to understand their state of alteration and geological origin. In addition, by raman analysis, the coloured layers of some painting samples from the porch wall were studied to analyse their composition, thickness and raw materials used in the pigments. The purpose of the research is to contribute to understanding the constructive technologies of the Roman Theater of the Maritime Theater through the identification of materials.