Knowledge on the extent and pattern of genetic variability present in a population of any crop is absolutely essential for further improvement and breeding. Similarly, information on the extent and nature of interrelationship among characters in sesame help in formulating efficient scheme of multiple trait selection. Besides, knowledge of the naturally occurring diversity in a sesame population helps to identify diverse groups of genotypes that can be useful for the breeding program. Little information was generated in regard to sesame genetic diversity and variability so far. Any breeding activity or selection for the crop improvement of crops in general & in sesame in particular takes into account the information on the magnitude of interrelationship among agronomic characters, their relationship with grain yield as well as their direct influence on grain yield. This book gives a detail analysis and investigation on the extent and magnitude of genetic variability and association of characters among the sesame local land races of Ethiopia.