A thorough and extensive germplasm exploration survey was undertaken during 2009 and 2010 to assess the distribution and variability in seed traits of Jatropha curcas L. in Senegal. Nineteen accessions from different agro ecological zones of the country were collected to evaluate variability in seed characters. Trees aged at least 5 years only were considered. Among the seed traits studied, 100 seed weight ranged from 63.68 to 77.83 g and seed length from 17.89 to 19.15 mm. The highest 100 seed weight (77.83 g) was recorded for the accession Jc-16 collected from Mampatim. Accessions from Soudanian zone showed high values of seed traits while low seed traits were recorded in Soudano-Sahelian zone. Variability in seed traits was not linked to geographic location. Old plantations of Jatropha curcas are spread in the central, south and coastal zones of Senegal where the species is well known by the populations. However, the species was least represented above 400 mm isohyet and unfamiliar. No old plantation was observed in extreme north of Senegal.