If you have not received your copy of our earnings press release, you may get one from the Investors section of our website at perkinelmer.com or from our toll-free investor hotline at (877) PKI-NYSE. Please note, this call is being webcast live and will be archived in our website until May 10, 2012.
Before we begin, we need to remind everyone of the Safe Harbor Statement that we've 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 to 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 that attachment, we will provide reconciliations promptly.
I'm now pleased to introduce the Chairman and Chief Executive Officer of PerkinElmer, Rob Friel.Robert F. Friel Thanks, Dave. Good afternoon and thank you, for joining us today. I'm pleased to report that we had another very good quarter in which we delivered strong financial results while making excellent progress against our 2012 strategic priorities. During the first quarter, we grew adjusted revenue 16% year-over-year, delivering better than expected growth despite very difficult comps from the first quarter of last year, particularly in Environmental Health, which grew 17% organically in the first quarter of 2011. In the first quarter of this year, Human Health increased adjusted revenue by 27% due to the addition of Caliper and solid organic growth from Diagnostics and Medical Imaging.