Holding in Company

Tullow Oil PLC
17 May 2006

                   Tullow Oil plc ('Tullow' or 'the Company')



Holding in Company



On 17 May 2006, Tullow received notification that Merrill Lynch & Co., Inc had a
notifiable interest at 15 May 2006 in 92,372,041 ordinary shares of 10p each in
the Company which represents 14.21% of the issued share capital of Tullow.



This total holding is held by a number of holding companies of Merrill Lynch
Investment Managers Group Limited and by certain other companies. Of the
92,372,041 ordinary shares in which Merrill Lynch & Co., Inc has a notifiable
interest, Merrill Lynch Investment Managers Group Limited has a notifiable
interest of 92,163,241 shares (14.18%).



Tullow has been informed that as at 15 May 2006 the shares held by Merrill Lynch
Investment Managers Group Limited to which this notification relates were
registered as follows:



Registered Holder                                 Number
Beneficial

(if known)                                 Of Shares
Interests



Nutraco Nominees Ltd              49,492,845         No

(Designated and Undesignated)



Britel (MAM) Nominees Ltd                 1,095,700                      No



Merrill Lynch Pension                     83,111                      Yes

Nominees Ltd



Merrill Lynch Pension                5,053,569         Yes

Nominees Ltd A/C Noncert



Treasury of the                                      1,169,958         No

Government of the Isle of Man

Nominees A/C 5



Treasury of the                                       2,033,653        No

Government of the Isle of Man

Nominees A/C 10



Stamford Nominees                                   180,300         No

Limited A/C CHARTY



Other names                             33,054,105         No



Total                                         92,163,241







This announcement has been issued through the Companies Announcement Service of

                           The Irish Stock Exchange.




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