[en] Sesame (Sesamum indicum L.) is an ancient oil crop considered to be still at an early stage in breeding. The fact that sesame is a crop of mainly developing countries with limited available research funds for long term breeding programmes, resulted in very few breeding efforts in research stations. Furthermore, sesame is not a mandate crop of any of the international agriculture research centers. Until recently most of the released sesame varieties in countries such as China, India and the Republic of Korea were the product of selection and pedigree breeding. A major constraint in this approach was the lack of sufficient genetic variation within the existing germplasm collections, especially for traits such as resistance to various diseases and seed retention. This is where mutation techniques could offer a possible solution. The United Nations Food and Agriculture Organization (FAO) organized some expert consultations on sesame breeding between 1981 and 1987, which all recommended the use of mutation induction for the enhancement of genetic variability with a focus on the following traits: modified plant architecture, seed retention, and resistance to diseases and pests. As a result, most of these recommendations have been included in this five year co-ordinated research project (CRP) that started in 1993, organized by the Plant Breeding and Genetics Section of the Joint FAO/IAEA Division. This CRP focused on the induction of the above mentioned characters in different sesame improvement programmes, and on the enhancement of co-operation between sesame breeders in developed and developing countries. Each participant covered a number of traits important for their specific breeding needs. During regular meetings under this project the participants had the opportunity to jointly appraise and evaluate sesame mutants and varieties in demonstration fields, thus strengthening the mutual effort for the genetic improvement of sesame through mutation techniques. The success of this CRP is documented by the official release of 12 sesame varieties in Egypt, India, Republic of Korea, Sri Lanka, and the more than 140 agronomically useful sesame mutants developed by the participants. More mutant varieties will be released in other countries in the near future as a direct spin-off from this project. Besides, the established collaborative links between sesame breeders of the participating countries and the exchange of germplasm has been and will be invaluable for the further advancement of sesame breeding and improvement of production