Exhibit 31.1



THE LUBRIZOL CORPORATION

Rule 13a-14(a)
Certification



I, James L. Hambrick, certify that:



1. I have reviewed this quarterly report on Form 10-Q of The Lubrizol Corporation;



2. Based on my knowledge, this report 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 report;



3. Based on my knowledge, the consolidated 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 registrant as of, and for, the periods presented in this report;



4. The registrant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 registrant and we 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 registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;



b) evaluated the effectiveness of the registrants disclosure controls
and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based upon such evaluation;



c) disclosed in this report any change in registrants internal control
over financial reporting that occurred during registrants most recent fiscal quarter that has materially affected, or is reasonably likely to materially affect, the registrants internal control over financial reporting; and



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



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 registrant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 registrants internal control over financial reporting.



|                                                       
|-------------------------------------------------------
|                                                       
|/s/    James L. Hambrick                               
|                                                       
|James L. Hambrick Chief Executive Officer and President



May 6, 2004



35



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Exhibit 31



THE LUBRIZOL CORPORATION

Rule 13-14(a)
Certification



I, Charles P. Cooley, certify that:



1. I have reviewed this quarterly report on Form 10-Q of The Lubrizol Corporation;



2. Based on my knowledge, this report 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 report;



3. Based on my knowledge, the consolidated 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 registrant as of, and for, the periods presented in this report;



4. The registrant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 registrant and we 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 registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;



b) evaluated the effectiveness of the registrants disclosure controls
and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based upon such evaluation;



c) disclosed in this report any change in registrants internal control
over financial reporting that occurred during registrants most recent fiscal quarter that has materially affected, or is reasonably likely to materially affect, the registrants internal control over financial reporting; and



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



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 registrant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 registrants internal control over financial reporting.



|                                         
|-----------------------------------------
|                                         
|/s/    Charles P. Cooley                 
|                                         
|Charles P. Cooley Chief Financial Officer



May 6, 2004



36