This study evaluates the compressive strength of mortars prepared with Ecuadorian Selva Alegre GU cement, following the NTE INEN 488:2009 standard. The research focuses on analyzing the effect of the water-to-cement ratio on compressive strength at different curing ages (3, 7, 14, 28, and 56 days), using standard 50 mm cubic specimens. Experimental procedures were conducted under control laboratory conditions, incorporating fine aggregates from the Guamote quarry in the Andean region. The project aims to determine the optimal mix proportions that enhance structural performance and comply with national technical standards. Key variables include granulometry, curing processes, and the physical characteristics of the aggregates. Findings are expected to offer technical guidelines for the quality control of mortars in structural applications, particularly in seismic-prone regions like Ecuador. The results will also contribute to optimizing material use on construction sites and ensuring consistency in compressive strength outcomes. This research highlights the importance of rigorous testing and specification compliance to improve the durability, safety, and structural reliability of cement-based construction materials.