By developing a new ontological argument for the existence of God, Joshua R. Sijuwade presents an innovative approach that enriches the existing discourse with fresh insights and a contemporary perspective. The ontological argument seeks to demonstrate the existence of God from an a priori standpoint and Sijuwade begins by addressing the substantial critique the modal argument has received. He embarks on a rigorous exploration, providing needed analysis and a positive iteration termed the ‘Rational Ontological Argument’, rooted in a novel modal methodology known as Rational Modal Realism. Using this new method, Sijuwade focuses on demonstrating how the central concepts and theories within modal metaphysics and epistemology—such as modal realism, modal rationalism, trope theory and ontological pluralism—offer a means to develop a victorious ontological argument. Employing contemporary analytic methods and suggesting productive directions for further research, Sijuwade makes a key contribution to philosophy of religion and re-invigorates the age-old philosophical argument for the existence of God.