**Exhibit 12.1**

 

**CERTIFICATION**

 

I, Carlos Augusto Lira Aguiar, certify that:

 

1.                                      I have reviewed this annual report on Form 20-Fof Fibria Celulose S.A. (the “company”);

 

2.                                      Based on my knowledge, this report doesnot contain 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 financial statements,and other financial information included in this report, fairly present in allmaterial respects the financial condition, results of operations and cash flowsof the company as of, and for, the periods presented in this report;

 

4.                                      The company’s other certifying officerand I are responsible for establishing and maintaining disclosure controls andprocedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e))and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and15d-15(f)) for the company and have:

 

(a)                                 Designed such disclosure controls andprocedures, or caused such disclosure controls and procedures to be designedunder our supervision, to ensure that material information relating to thecompany, including its consolidated subsidiaries, is made known to us by otherswithin those entities, particularly during the period in which this report isbeing prepared;

 

(b)                                Designed such internal control overfinancial reporting, or caused such internal control over financial reportingto be designed under our supervision, to provide reasonable assurance regardingthe reliability of financial reporting and the preparation of financialstatements for external purposes in accordance with generally accepted accountingprinciples;

 

(c)                                 Evaluated the effectiveness of thecompany’s disclosure controls and procedures and presented in this report ourconclusions about the effectiveness of the disclosure controls and procedures,as of the end of the period covered by this report based on such evaluation;and

 

(d)                                Disclosed in this report any change inthe company’s internal control over financial reporting that occurred duringthe period covered by the annual report that has materially affected, or isreasonably likely to materially affect, the company’s internal control overfinancial reporting; and

 

5.                                      The company’s other certifying officerand I have disclosed, based on our most recent evaluation of internal controlover financial reporting, to the company’s auditors and the audit committee ofthe company’s Board of Directors (or persons performing the equivalentfunctions):

 

(a)                                 All significant deficiencies and materialweaknesses in the design or operation of internal control over financialreporting which are reasonably likely to adversely affect the company’s abilityto record, process, summarize and report financial information; and

 

(b)                                Any fraud, whether or not material, thatinvolves management or other employees who have a significant role in thecompany’s internal control over financial reporting.

 

Dated:  April 30, 2010

 
| By:    | /s/ Carlos Augusto Lira  Aguiar |                       |
|--------|---------------------------------|----------------------------|
|   | Name:                           | Carlos Augusto Lira Aguiar |   |
|   | Title:                          | Chief Executive Officer    |   |

 

----