Exhibit 21 SUBSIDIARIES OF THE REGISTRANT YANKEE GAS SERVICES COMPANY is a wholly-owned subsidiary of the registrant. It is incorporated in Connecticut and does business under its own name. YANKEE ENERGY FINANCIAL SERVICES COMPANY is a wholly-owned subsidiary of the registrant. It is incorporated in Connecticut and does business under its own name. HOUSATONIC CORPORATION is a wholly-owned subsidiary of the registrant. It is incorporated in Connecticut and does business under its own name. NORCONN PROPERTIES, INC. is a wholly-owned subsidiary of the registrant. It is incorporated in Connecticut and does business under its own name. YANKEE ENERGY PRODUCTION SERVICES, INC. is a wholly-owned subsidiary of the registrant. It is incorporated in Connecticut and does business under its own name.