For over a decade, two workshops have been shaping the landscape of research in multimedia security. On one hand, Information Hiding (aka. IH) was created in 1996 and focused on digital watermarking, steganography and steganalysis, anonymity and privacy, hard to intercept communications and covert/subliminal channels. On the other hand, the ACM Workshop on Multimedia and Security (aka. ACM MMSec) was initiated in 1998 and focused on data hiding, robust/perceptual hash, biometrics, video surveillance, and multimedia forensics. Key seminal works have been published in these two workshops and papers accepted for publication there attracted over 9,000 citations in total. Year after year, the two communities grew closer and the overlap between their respective scope got bigger. As a result, after 14 successful editions each, IH and ACM MMSec decided to merge in a single event in an attempt to establish synergies between the two communities while building on the reputation obtained over the years. The 1st ACM Information Hiding and Multimedia Security Workshop (IH&MMSec) will be held at the University of Montpellier II, in southern France, on June 17-19, 2013. We hope that this first edition of this workshop, resulting from merging two long standing sustainable events, will give birth to an attractive research forum that will facilitate cross-fertilization of ideas among key stakeholders from academia, industry, practitioners and government agencies around the globe.