If you have not received your copy of our earnings press release, you may get one from the Investors section of our website at www.perkinelmer.com or from our toll-free investor hotline in 1 (877) PKI-NYSE. Please note, this call is being webcast live and will be archived in our website until August 16, 2012.
Before we start, we need to remind everyone of the Safe Harbor Statement that we have outlined in our earnings press release, issued earlier this afternoon and also those in our SEC filings. Any forward-looking statements made today represent our views only as of today. We disclaim any obligation to update forward-looking statements in the future, even if our estimates change. So you should not rely on any of today's forward-looking statements as representing our views as of any date after today.
During this call, we will be referring to certain non-GAAP financial measures. A reconciliation of the non-GAAP financial measures we plan to use during this call to the most directly comparable GAAP measures is available as an attachment to our earnings press release. To the extent we use non-GAAP financial measures during this call, but are not reconciled to GAAP in the attachment, we will provide reconciliations promptly.
I'm now pleased to introduce the Chairman and Chief Executive Officer of PerkinElmer, Rob Friel. Rob?Robert F. Friel Thanks, Tommy. Good afternoon, and thank you for joining us today. Once again, we are reporting another excellent quarter, in which we delivered solid financial results while making excellent progress against our strategic priorities. During the second quarter, our adjusted revenue grew 10% year-over-year, adjusted operating margins expanded 240 basis points. We generated excellent cash flow and adjusted earnings per share increased 23%, which exceeded both our guidance and consensus. We continue to be extremely pleased with how we are improving both operating efficiencies and profitability of the company, while also delivering very strong top line growth. Our ability to deliver this impressive financial performance, particularly in light of the current difficult macroeconomic conditions, is due to several factors.