Our strong performance in the first half puts us in very good position to achieve our revenue and earnings goals for the full year. I'll frame my remarks this morning by first covering the financial highlights, give you a sense of what we're seeing in our key end markets relative to our results, and then review some of the exciting new developments we announced during the quarter and in recent weeks.
First, the financials. As I mentioned, we delivered record adjusted EPS again this quarter, a 23% increase over 2011. Our revenue grew by 9% over last year. Our adjusted operating income increased 16% in Q2, and we achieved 110 basis points of adjusted operating margin expansion. Our Q2 results clearly show that our teams are focused on the right priorities. Our growth initiatives are delivering real value for our customers, and our ongoing cost actions are strengthening the bottom line. On the growth side of the equation, our investments in Asia-Pacific are really paying off, with strong results again this quarter. I'll mention a little more on that in a few moments.
In new products, we're seeing nice uptick across our analytical instruments portfolio, and we continue to innovate to keep that pipeline full. Our unique value proposition is clearly resonating across a broader customer set from pharma and biotech where we initiated the approach, to medical device manufacturers, reference and contract testing labs as well.
Turning to cost actions for a moment. This is an area that we're always extremely focused on, and is a key contributor to our margin expansion. Our PPI and PPI Lean business systems are way of life of Thermo Fisher, and they helped earn us a reputation for operational excellence. Well, PPI is just one of the ways that we drive margin expansion. As you know, we have multiple levers we can pull and in the environment we're managing through today, this gives us the ability to quickly adapt to changing market conditions.