AMERICAN TOWER CORP /MA/ — Director's Dealing 2011

Jun 3, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: AMERICAN TOWER CORP /MA/ (AMT)
CIK: 0001053507
Period of Report: 2011-06-01

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

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-06-01	Class A Common Stock	M	25545	$28.39	Acquired	40783	Direct
2011-06-01	Class A Common Stock	S	23174	$54.83	Disposed	17609	Direct
2011-06-01	Class A Common Stock	S	2371	$55.40	Disposed	15238	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-06-01	Option to Purchase Class A Common Stock	$28.39	M	25545	Disposed	2019-03-10	Class A Common Stock (25545)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Class A Common Stock	3662	Indirect

Footnotes

F1: The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan.

F2: Represents the weighted average price of shares sold in multiple same-day transactions at prices ranging from $54.28 to $55.27 per share.

F3: Represents the weighted average price of shares sold in multiple same-day transactions at prices ranging from $55.28 to $55.50 per share.

F4: This option was granted pursuant to the 2007 Equity Incentive Plan and is exercisable in 25% cumulative annual increments beginning March 10, 2010.