We are delighted to present the proceedings of the 5th International Workshop on Modeling Autonomic Communication Environments (MACE 2010). This wo- shopwasheldaspartofthe6thInternationalConferenceonNetworkandService Management (CNSM 2010), formerly known as and building on the success of the MANWEEK conference series. This year we met just a hundred yards away from Niagara Falls in Canada, a very exciting location. MACE started as an experiment and over the past years has created a small yet very active community that convened again this year to discuss and evaluate new advances, innovative ideas, and solid developments. The main focus of MACE, combining modeling with communications, is certainly a hard topic that requires a lot of discussion, thus the work presented at the workshop is intrinsically debatable and might not be as practiced as in other well-established workshops, but this was the nature of MACE from the beginning. New ideas, sometimes more, sometimes less rough around the edges (and some of them even inside) are submitted and provoke extensive discussions. The field in which we are working relies on these discussions, or even adventures, and we have this year again strongly motivated and supported a variety of novel work in the technical program. This year, the submissions, while being closely related to the main themes, brought some new areas into the workshop. We still see architectural design and the application of autonomic principles to networks and services, but we also now have submissions looking into previously unexplored areas such as Home Area Networks, multimedia streaming, virtualization, federation, and user experience. This portrays a maturity in the domain, which has by now gone through several cycles, and improves its outputs by applying the lessons learned.