Efforts in the domain of mobile health, or mHealth, have been criticized for the unfettered proliferation of pilots and a lack of a rigorous evidence base to support these strategies. In this letter, we present the response of a group of researchers in the mHealth community to the recent calls for evidence issued by global health and funding agencies. We support our conclusions through a summary of the numerous ongoing mHealth studies listed in the US federal clinical trial registry. We conducted a search on the US federal clinicaltrials.gov database using the keywords "mHealth", "mobile" or "cell AND phone" to obtain 1678 results of studies. We manually inspected each result to check if it fit the purview of an mHealth study. Studies that were terminated or withdrawn prior to submission were excluded. We identified 215 unique mHealth studies that were registered in the clinicaltrials.gov database, of which 8.4% (n=18) were observational in nature while the remaining 91.6% (n=197) were interventional. Of the 215 studies, 81.8% (n=176) studies used a classical randomized trial design and 40 new studies were added to the database between May and November 2012 alone. Based on these results, we posit that the field is entering a new 'era' where a body of rigorous evaluation of mHealth strategies is rapidly accumulating. The transition into an era of evidence-based mHealth supports our position that innovation in this domain can be evaluated with the same rigor as other public health strategies, attenuating some of the hype previously associated with mHealth. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.