This in vitro study aimed to evaluate and compare the compressive strength of two different core materials used in restorative dentistry: a composite resin (Filtek Z250) and a glass-ionomer cement (Fuji IX). For each material, a total of 20 cylindrical samples were fabricated, and compressive stress analysis was performed using a universal testing machine. The results showed that the mean compressive strength of the composite resin (Filtek Z250) was significantly higher than that of the glass-ionomer cement (Fuji IX). Specifically, the mean compressive strength of Filtek Z250 was 364.25 MPa, while that of Fuji IX was 137.45 MPa. These findings suggest that the composite resin (Filtek Z250) may be the better choice for restorations requiring high compressive strength. However, further studies are needed to evaluate other mechanical properties and clinical performance of these materials.