##### 





---



20-F/A (Amendment No. 1) 2002




---



Exhibit 99.1

I, Jeroen van der Veer, certify
that:

|   |                                                                                                                                                                                                                                                                                                                                                 
|-- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|1. | I have reviewed this Amendment No. 1 on
    Form 20-F/A of Royal Dutch Petroleum Company (N.V.
    Koninklijke Nederlandsche Petroleum Maatschappij);                                                                                                                                                                                           
|  
|2. | Based on my knowledge, this Amendment No. 1 does
    not contain any untrue statement of a material fact or omit to
    state a material fact necessary to make the statements made, in
    light of the circumstances under which such statements were
    made, not misleading with respect to the period covered by this
    Amendment No. 1;
|  
|3. | Based on my knowledge, the financial statements,
    and other financial information included in this report, fairly
    present in all material respects the financial condition,
    results of operations and cash flows of the company as of, and
    for, the periods presented in this Amendment No. 1;                                   
|  
|4. | The companys other certifying officer and I
    are responsible for establishing and maintaining disclosure
    controls and procedures (as defined in Exchange Act
    Rules 13a-15(e) and 15d-15(e)) for the company and have:                                                                                                               



| |     |                                                                                                                                                                                                                                                                                                                                                                                                             
| | --- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | (a) | Designed such disclosure controls and procedures,
    or caused such disclosure controls and procedures to be designed
    under our supervision, to ensure that material information
    relating to the company, including its consolidated
    subsidiaries, is made known to us by others within those
    entities, particularly during the period in which this Amendment
    No. 1 is being prepared;
|
| | (b) | Evaluated the effectiveness of the companys
    disclosure controls and procedures and presented in this
    Amendment No. 1 our conclusions about the effectiveness of the
    disclosure controls and procedures, as of the end of the period
    covered by this Amendment No. 1 based on such evaluation; and                                                                                          
|
| | (c) | Disclosed in this report any change in the
    companys internal control over financial reporting that
    occurred during the period covered by the Amendment No. 1 that
    has materially affected, or is reasonably likely to materially
    affect, the companys internal control over financial
    reporting;                                                                                      



|   |                                                                                                                                                                                                                                                                                                       
|-- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|5. | The companys other certifying officer and I
    have disclosed, based on our most recent evaluation of internal
    control over financial reporting, to the companys auditors
    and the audit committee of the companys board of directors
    (or persons performing the equivalent functions):



| |     |                                                                                                                                                                                                                                                                                       
| | --- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | (a) | All significant deficiencies and material
    weaknesses in the design or operation of internal control over
    financial reporting which are reasonably likely to adversely
    affect the companys ability to record, process, summarize
    and report financial information; and
|
| | (b) | Any fraud, whether or not material, that involves
    management or other employees who have a significant role in the
    companys internal control over financial reporting.                                                                                                       

Dated July 2, 2004

The Hague

/s/Jeroen van der
Veer

--------------------------------------------------------------------


Jeroen van der Veer

President and Managing Director




Exhibits      E9