Provided is a pharmaceutical formulation in the form of a bilayered tablet consisting of a first layer containing irbesartan or a pharmaceutically acceptable salt thereof and a second layer containing an HMG-CoA reductase inhibitor and a basic additive, which can improve the dissolution rate and stability of irbesartan and an HMG-CoA reductase inhibitor to enhance the bioavailability of the drug compared to conventional complex formulations and to minimize the generation of the related compounds, thereby being effectively used as a stable and superior therapeutic agent for hypertension and hypercholesterolemia.