Holding in Company

Tullow Oil PLC
13 March 2008



TR-1(i): NOTIFICATION OF MAJOR INTERESTS IN SHARES



1. Identity of the issuer or the underlying issuer of existing shares to which
voting rights are attached:



TULLOW OIL PLC



2. Reason for the notification (please tick the appropriate box or boxes)



An acquisition or disposal of voting rights:                                (X)



An acquisition or disposal of financial instruments which may result in the
acquisition of shares already issued to which voting rights are attached:

    (  )



An event changing the breakdown of voting rights:                  (  )



Other (please specify):
       (  )



3. Full name of person(s) subject to the notification obligation:



BlackRock, Inc.



4. Full name of shareholder(s) (if different from 3.):





5. Date of the transaction (and date on which the threshold is crossed or
reached if different):



11 March 2008



6. Date on which issuer notified:



    12 March 2008



7. Threshold(s) that is/are crossed or reached:



    Gone below 13%



8. Notified details:













A: Voting rights attached to shares


Class/type of shares if possible              Situation previous to the Triggering transaction
using the ISIN CODE
                                  Number of shares                   Number of voting Rights
Ord 10p
GB0001500809                      100,302,314                        100,302,314


Resulting situation after the triggering transaction (vii)


Class/type of shares if      Number of shares         Number of voting rights           % of voting rights
possible using the ISIN CODE

                             Direct                   Direct       Indirect             Direct      Indirect



Ord 10p                       N/A                      N/A         93,356,120           N/A         12.97%

GB0001500809





















B: Financial Instruments



Resulting situation after the triggering transaction


Type of financial instrument                                  Expiration Exercise/          Number of voting   % of
                                                              Date       Conversion Period/ rights that may be voting
                                                                         Date               acquired if the    rights
                                                                                            instrument is
                                                                                            exercised/
                                                                                            converted.




Total (A+B)
Number of voting rights        % of voting rights



93,356,120                     12.97%





9. Chain of controlled undertakings through which the voting rights and/or the
financial instruments are effectively held, if applicable:



Proxy Voting:



10. Name of the proxy holder:





11. Number of voting rights proxy holder will cease to hold:





12. Date on which proxy holder will cease to hold voting rights:





13. Additional information:



14. Contact name:



Richard Taylor, Deputy Company Secretary





15. Contact telephone number:



0208 996 1000

















This announcement has been issued through the Companies Announcement Service of

                           the Irish Stock Exchange.






                      This information is provided by RNS
            The company news service from the London Stock Exchange