The dividend will be payable on Oct. 14, 2011 to shareholders of record as of Sept. 23, 2011.
The quarterly dividend comes more than a month after Iron Mountain declared its financial results for the second quarter ended June 30, 2011.
The Boston, Massachusetts based company reported total revenues of $763 million, a 5 percent increase compared to the same quarter 2010.
Based on its strong performance during the second quarter, Iron Mountain had said that it will achieve financial goals for the year 2011.
In June this year, the company had declared quarterly dividend of of $0.25 per share, paid on July 15, 2011 to shareholders of record as of June 24, 2011. This was 33 percent increase over the previous dividend.