EXHIBIT 21 WESTWOOD ONE, INC. LIST OF SUBSIDIARIES WESTWOOD ONE RADIO, INC. WESTWOOD ONE RADIO NETWORKS, INC. WESTWOOD NATIONAL RADIO CORPORATIONS, INC. WESTWOOD ONE STATIONS - NYC, INC. WESTWOOD ONE PROPERTIES, INC. SMARTROUTE SYSTEMS, INC. METRO NETWORKS, INC. METRO NETWORKS COMMUNICATIONS, INC. METRO NETWORKS SERVICES, INC. METRO NETWORKS COMMUNICATIONS, LIMITED PARTNERSHIP