Although the Mediterranean region is where settled agriculture began, and the center of origin of many world crops such as cereals and legumes, it is mainly a food-deficit area largely due to low-rainfall conditions. Rotation involving fallow was a traditional strategy to combat drought. Due to population pressure much change has occurred in the past few decades; increasing land use intensification, less fallow and more monoculture and alternative crops, increasing fertilizer use, changes in tillage and residue management practices, and increased irrigation from mainly rainfed systems. The sustainability of new cropping systems can only be assessed by long-term trials. However, in contrast to USA, Canada, and Australia, such trials are relatively rare in the Mediterranean environment, and they are recent, except in Egypt. In the past 25 years, several multi-year rotation and tillage cropping system trials have been conducted in Syria. Other major dryland cropping trials have been conducted in Morocco, Turkey, Cypress, and more recently in Lebanon. While most of these trials have been terminated, some are still surviving. A number of irrigated trials were conducted in Egypt. The purpose of this presentation is to distill the essence of these trials, highlighting what has been achieved and examining the future needs and prospects for long-term rotation trials in today's rapidly changing agriculture.