**Exhibit 31.2**

 

###### **Form of Rule 13a-14(a) [Section 302] Certification**

######  

***CERTIFICATIONS***

 

I,David V. Smith, certify that:

 

*1.**             *I have reviewed this Quarterly Report onForm 10-Q of Chiron Corporation;

 

*2.**             *Based on my knowledge, this report does notcontain any untrue statement of a material fact or omit to state a materialfact necessary to make the statements made, in light of the circumstances underwhich such statements were made, not misleading with respect to the periodcovered by this report;

 

*3.**             *Based on my knowledge, the financialstatements, and other financial information included in this report, fairlypresent in all material respects the financial condition, results of operationsand cash flows of the registrant as of, and for, the periods presented in thisreport;

 

*4.**             *The registrant’s other certifying officer(s)and I are responsible for establishing and maintaining disclosure controls andprocedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) andinternal control over financial reporting (as defined in Exchange Act Rules13a-15(f) and 15d-15(f)) for the registrant and have:

 

*a) *Designed such disclosure controls and procedures, or caused suchdisclosure controls and procedures to be designed under our supervision, toensure that material information relating to the registrant, including itsconsolidated subsidiaries, is made known to us by others within those entities,particularly during the period in which this report is being prepared;

 

*b) *Designed such internal control over financial reporting, or caused suchinternal control reporting over financial reporting to be designed under oursupervision, to provide reasonable assurance regarding the reliability offinancial reporting and the preparation of financial statements for externalpurposes in accordance with generally accepted accounting principles;

 

*c)  *Evaluated the effectiveness of the registrant’s disclosure controls andprocedures and presented in this report our conclusions about the effectivenessof the disclosure controls and procedures, as of the end of the period coveredby this report based on such evaluation; and

 

*d) *Disclosed in this report any change in the registrant’s internal controlover financial reporting that occurred during the registrant’s most recentfiscal quarter (the registrant’s fourth fiscal quarter in the case of an annualreport) that has materially affected, or is reasonably likely to materiallyaffect, the registrant’s internal control over financial reporting; and

 

*5.**             *The registrant’s other certifying officers andI have disclosed, based on our most recent evaluation of internal control overfinancial *reporting*, to theregistrant’s auditors and the audit committee of registrant’s board ofdirectors (or persons performing the equivalent function):

 

*a) *All significant deficiencies and material weaknesses in the design oroperation of internal control over financial reporting which are reasonablylikely 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 otheremployees who have a significant role in the registrant’s internal control overfinancial reporting.

 

DATE:April 6, 2005

 
|   | /s/ DAVID V. SMITH                                           | * * |
|--------|--------------------------------------------------------------|----------|
|   |                                                         |     |
|   | David V. Smith*Vice  President and Chief Financial  Officer* |     |

 

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