EXHIBIT 99.01
Hampshire International Business Park Chineham Basingstoke Hampshire RG24 8EP United Kingdom Tel +44 (0)1256 894000 Fax +44 (0)1256 894708 www.shire.com
Press Release

20 September 2005

Shire Pharmaceuticals Group plc (the "Company")

The Company announces that it was notified on 19 September 2005 under Sections 198 to 202 of the Companies Act that Barclays PLC, through its associated companies, held a notifiable interest, in aggregate, of 16,142,551 ordinary shares of £0.05p each in the capital of the Company. These holdings represent 3.27 per cent of the issued ordinary share capital of the Company.

T May
Company Secretary

For further information please contact:
Investor Relations	Cléa Rosenfeld (Rest of the World)	+44 1256 894 160
	Brian Piper (North America)	+1 484 595 8252

Notes to editors

Shire Pharmaceuticals Group plc

Shire Pharmaceuticals Group plc (Shire) is a global specialty pharmaceutical company with a strategic focus on meeting the needs of the specialist physician and currently focuses on developing and marketing products in the areas of central nervous system (CNS), gastrointestinal (GI), renal diseases and human genetics. Shire has operations in the world’s key pharmaceutical markets (US, Canada, UK, France, Italy, Spain and Germany) as well as a specialist drug delivery unit in the US.

For further information on Shire, please visit the Company’s website: www.shire.com.

Registered in England 2883758 Registered Office as above