McCann Erickson Worldwide Advertising is the world's largest and most globally experienced advertising agency network. With offices in over 130 countries and more than 75 years of global experience, McCann Erickson is the leader in multinational advertising, handling more global accounts than any other ad agency. Its global resources, combined with its local expertise, have made McCann Erickson a Top 5 agency in almost every market in which it operates.