EXHIBIT 8.1 Subsidiaries of Elan Corporation, plc Registered Office & Group Jurisdiction of Incorporation Company Nature of Business Share % and Operation - ------- ------------------ ------- ----------------------------- Elan International Services Ltd. Financial services company 100 Clarendon House, 2 Church St. Hamilton, Bermuda Elan Management Ltd. Provision of management 100 Lincoln House, Lincoln Place services Dublin 2, Ireland Elan Pharmaceuticals, Inc. Research and development 100 800 Gateway Blvd. and sale of South San Francisco, CA, pharmaceutical products United States (a Delaware corporation) Athena Neurosciences, Holding company 100 800 Gateway Blvd. Inc. South San Francisco, CA, United States (a Delaware corporation) Elan Pharma International Ltd. Research and 100 WIL House, Shannon Business Park development, sale and Co. Clare, Ireland distribution of pharmaceutical products and financial services Elan Pharma Ltd. Manufacture of 100 Monksland, Athlone pharmaceutical products Co. Westmeath, Ireland Elan Finance Corporation Ltd. Financial services company 100 Clarendon House, 2 Church St. Hamilton, Bermuda Elan Pharmaceutical Investment holding 100 Clarendon House, 2 Church St. Investments III, Ltd. company Hamilton, Bermuda Elan Holdings Ltd. Holding company 100 Monksland, Athlone Co. Westmeath, Ireland Elan Holdings Inc. Manufacture, marketing 100 1300 Gould Drive and distribution of Gainesville, GA pharmaceutical and United States medical device products (a Delaware corporation) Elan Drug Delivery, Inc. Research and development 3000 Horizon Drive King of Prussia, PA United States (a Delaware corporation) Elan Capital Corporation Ltd Financial services company 100 Clarendon House, 2 Church St Hamilton, Bermuda Monksland Holdings BV Financial services company 100 Amsteldijte 166 6th Floor 1079 LH Amsterdam The Netherlands
