EXHIBIT 31.2

SARBANES-OXLEY SECTION 302(a) CERTIFICATION

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|I, Chad C.
Braun, certify that:
|                                |    |                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                        
|                                | 1. | I have
reviewed this Quarterly Report on Form 10-Q of AmREIT Monthly Income &
Growth Fund III, Ltd.;                                                                                                                                                                                                                                   
|                                |    |                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                        
|                                | 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 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(s) 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)) and internal control over
financial reporting (as defined in Exchange Act Rules 13a-15(f) and
15d-15(f)) for the registrant 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 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)                                                                                                                                                                                                                                                                                                                                      | Designed
such internal control over financial reporting, or caused such internal
control over financial reporting to be designed under our supervision, to
provide reasonable assurance regarding the reliability of financial reporting
and the preparation of financial statements for external purposes in
accordance with generally accepted accounting principles;                
|                                |    |                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                        
|                                |    | c)                                                                                                                                                                                                                                                                                                                                      | 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 on such evaluation; and                                                                                                    
|                                |    |                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                        
|                                |    | d)                                                                                                                                                                                                                                                                                                                                      | Disclosed in
this report any change in the registrants internal control over financial
reporting that occurred during the registrants most recent fiscal quarter
(the registrants fourth fiscal quarter in the case of an annual report) 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(s) 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 the registrant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 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.                                                                                                                                                                                                             

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|---------------------- |  | ------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|Date:     May 13, 2011 |  | By:    | /s/ Chad C. Braun                                                                                                                                                                                                          
|                       |  | Name:  | Chad C. Braun                                                                                                                                                                                                              
|                       |  | Title: | Executive Vice President, Chief Financial Officer, Chief Operating Officer, Treasurer and Secretary of AmREIT
Monthly Income & Growth III Corporation, the General Partner of AmREIT Monthly Income & Growth Fund III, Ltd.

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