Disclosed are an electrolyte membrane for fuel cells that can prevent poisoning of catalysts and a method of producing the same. The electrolyte membrane for fuel cells includes an ion transport layer including an ionomer having proton conductivity, and a catalytic composite dispersed in the ion transport layer, wherein the catalytic composite includes a catalytic particle including a catalytic metal component having an activity of decomposing hydrogen peroxide, and a protective layer formed on at least a part of a surface of the catalytic particle to prevent the ionomer from contacting the catalytic metal component.