AMERICAN TOWER CORP /MA/ — Director's Dealing 2012

Feb 28, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: AMERICAN TOWER CORP /MA/ (AMT)
CIK: 0001053507
Period of Report: 2012-02-24

Reporting Person: HESS WILLIAM H (EVP, Int'l. Operations)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-02-24	Common Stock	M	3174	$31.50	Acquired	8968	Direct
2012-02-24	Common Stock	M	2665	$37.52	Acquired	11633	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-02-24	Option to Purchase Common Stock	$31.50	M	3174	Disposed	2016-03-01	Common Stock (3174)	Direct
2012-02-24	Option to Purchase Common Stock	$37.52	M	2665	Disposed	2017-03-15	Common Stock (2665)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	5095	Indirect

Footnotes

F1: As a result of a computational error, the amount of securities reported as beneficially owned on the Form 4 filed by the reporting person on September 20, 2011 was overstated by 20 shares. The amount of securities reported as beneficially owned on this Form 4 has been adjusted accordingly.

F2: This option was granted pursuant to the 1997 Stock Option Plan, as amended, and is exercisable in 25% cumulative annual increments beginning March 1, 2007.

F3: This option was granted pursuant to the 1997 Stock Option Plan, as amended, and is exercisable in 25% cumulative annual increments beginning March 15, 2008.