EXHIBIT 31.2

SARBANES-OXLEY SECTION 302(a) CERTIFICATION

I, Chad C.
Braun, certify that:

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| | 1. | I have
 reviewed this Annual Report on Form 10-K of AmREIT Monthly Income &
 Growth Fund III, Ltd.;                                                                                                                                                                                                                                         
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| | 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;                              
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| | 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;                                                 
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| | 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:
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| |    | 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                                                                                                      
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| |    | 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
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| | 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):                                      
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| |    | 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.                                                                                                                                                                                                                

|      |                 |       |                                                              
|----- | --------------- | ----- | -------------------------------------------------------------
|Date: | March 10,
 2010 | By:   | /s/
 Chad C. Braun                                           
|      |                 | Name: | Chad
 C. Braun                                               
|      |                 | Title | Executive
 Vice President, Chief Financial 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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