This paper presents the preliminary findings on a new mortar prepared with alkali-activated seashell waste (AASW). Three mortars were manufactured with seashell waste to Activator ratios of 2.5, 3 and 3.5. The mechanical properties were determined, and the chemical products of each mixture were characterized using TG/DTG, XRD and FTIR analyses. From both an economic and an environmental point of view, the obtained results are very encouraging where they show that SW can be used as precursor to formulate an alkali-activated mortar with a compressive strength of 22 MPa and a porosity of 16.5%. The AASW paste was found to be mainly composed of C-S-H and different carbonates such as gaylussite, pirssonite and thermonatrite. In terms of mechanical strengths and porosity, it was established that the water to binder ratio is the key factor. Furthermore, the microstructural images showed a good compatibility between the AASW paste and aggregates.