Holding in Company

Tullow Oil PLC
19 September 2006

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



Holding in Company


On 18 September 2006, Tullow received notification that Merrill Lynch & Co., Inc had a notifiable interest at 13 
September 2006
in 90,754,405 ordinary shares of 10p each in the Company which represents 13.95% 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 90,754,405 ordinary shares in which Merrill Lynch & Co., Inc has a notifiable interest, Tullow has been informed 
that both Merrill Lynch Group,
Inc and Merrill Lynch Investment Managers Group Limited have notifiable interests of 90,635,153 shares (13.93%).

As at 13 September 2006, the shares held by Merrill Lynch Investment Managers Limited to which this notification relates
were registered as follows:

Registered Holder                                  Number                   Beneficial
(if known)                                              Of Shares                               Interests

Nutraco Nominees Ltd                           49,924,984               No
(Designated and Undesignated)

Britel (MAM) Nominees Ltd                      880,804               No

Treasury of the                                          812,442               No
Government of the Isle of Man
Nominees A/C 5

Treasury of the                                       1,833,653 No
Government of the Isle of Man
Nominees A/C 10

Merrill Lynch Pension                                  58,705                Yes
Nominees Ltd

Merrill Lynch Pension                              4,766,696 Yes
Nominees Ltd A/C Noncert

Stamford Nominees                                                   152,500               No
Limited A/C CHARTY

Other names                                          32,205,369               No

Total                                                      90,635,153







This announcement has been issued through the Companies Announcement Service of

                           The Irish Stock Exchange.






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