Greenhouse areas in Mediterranean regions have significantly increased in the last years.The majority of greenhouses in Mediterranean areas are very different from those used in Northern countries.In the North most green-houses are heated and covered with glass as a way to maximise solar radiation gain.In the South, where the air temperature is warmer and solar radiation is considerably higher, greenhouses are usually not heated and are covered with plastic films.Environmental control in such greenhouses is essentially achieved using natural ventilation techniques to control temperature and humidity.The main limiting factors for greenhouse cultivation are the low air temperature and high humidity levels during the night in winter, often too high temperature during the daytime period in spring/summer and CO2 depletion caused by insufficient ventilation, contributing to the lower productions compared with those in Northern countries.In order to be competitive, growers need to increase productivity, quality and/or to produce in periods out of season by using appropriate environmental control techniques, such as the improvement of ventilation systems and their management, use of passive and/or active heating or cooling systems, CO2 enrichment, and control and automation systems, beyond others.The use of these techniques usually implies energy consumption, increasing production costs and contributing to GHG emissions.In this paper the main constraints of greenhouse production in the Mediterranean region are analysed and solutions are proposed in order to increase production and at the same time improve energy use efficiency.