Various remarks that we make on this call concerning expectations, predictions, plans and prospects constitute forward-looking statements. These forward-looking statements are subject to risks and uncertainties that may cause actual results to differ from historical or anticipated results. Any forward-looking statements reflect the management's current view only, and Charter undertakes no obligation to revise or update such statements or to make additional forward-looking statements in the future.
During the course of today's call, we'll be referring to non-GAAP measures as defined and reconciled in this morning's earnings release. These non-GAAP measures, as defined by Charter, may not be comparable to measures with similar titles used by other companies.
In today's earnings release, we reported results in accordance with GAAP, as well as pro forma results for 2011. The pro forma results reflect the acquisition of certain cable systems in 2011, as if they had occurred on January 1, 2011, unless otherwise noted. The year-over-year growth rates we will be referring to this morning are on a pro forma basis.
Joining me on today's call are Tom Rutledge, President and CEO; and Chris Winfrey, our CFO. The presentation that accompanies their comments can be found on our website, charter.com, under Financial Information. The press release and trending schedules are also posted on our website under Investor & News Center.With that, I'll turn the call over to Tom. Thomas M. Rutledge Thank you, Robin. In the first quarter, we saw significant improvement in customer trends, and overall results were as planned. First quarter revenue was up nearly 3%, while adjusted EBITDA was down approximately 2% year-over-year. The change in adjusted EBITDA was primarily driven by the costs associated with accelerated customer growth. Free cash flow was $102 million this quarter versus $74 million in Q1 of last year. We gained 274,000 RGUs, more than double the net gain last year. We grew 20,000 video customers for the first quarterly video growth in 5 years. Internet customer additions grew by more than 50% year-over-year. And we added nearly 100,000 new relationships in the quarter, more than triple the gain 1 year ago.