[en] The stakes of embarking upon a Mediterranean Energy Transition is essential for countries from both shores of the Mediterranean, especially taking into account the increasing demographics (+105 million by 2040) and the fast growing energy demand in an increasingly constrained context both in terms of energy availability and environmental impacts of conventional energy sources uses. There is a huge, but yet untapped, potential for energy efficiency and renewable energy sources, especially in the South Mediterranean region. By improving energy efficiency and deploying renewables on a large scale, the Mediterranean region would reduce tensions on energy security for importing countries, improve opportunities for exporting ones and reduce energy costs and environmental damages for the whole region. Embarking on an energy transition path will also help improve social welfare in the region and contribute to job creation, among other positive externalities. OME regularly conducts prospective works to 2040, assessing the impact of prolonging current energy trends. Under this Business-As-Usual or so-called 'Conservative' Scenario the situation would evolve critically on all counts over the next 25 years: doubling of energy demand and tripling of electricity consumption, soaring infrastructure and import bills (+443 GW to be installed and doubling of the fossil-fuel imports) and a critical rise in carbon emissions (+45%). Such a scenario, based essentially on fossil fuels, would put further strain on the environment and exacerbate geopolitical tensions in the region. A change of energy trajectory is therefore necessary for all Mediterranean countries to help change current trends and to increase efforts promoting energy efficiency and renewable energies. In this context, MEDENER and OME, based on the 2030-2050 visions of ADEME and the prospective tools of OME, have decided to jointly investigate a Mediterranean Energy Transition Scenario, an ambitious scenario that goes beyond the plans and targets announced by governments and policy makers. The Energy Transition Scenario assumes the implementation of those measures that are currently the most technically, economically, and politically mature for large-scale roll-out of energy efficiency and renewable energies. This Scenario assumes no major technology breakthrough, but the deployment of existing technologies and sound energy efficiency policies and measures across all Mediterranean countries. (authors)