A line x tester analysis was carried-out by using 12 lines and 3 testers and their resulting 36 hybrids of sesame in order to estimate heterosis, combining ability and nature of gene action involved in the inheritance of seed yield and its components. The experiment was conducted at the Instructional Farm, College of Agriculture, JAU, Junagadh during kharif- 2012. Observations on five competitive randomly selected plants per replication per treatment were recorded on 15 characters and the mean values were subjected to analysis of variance, estimation of heterosis and combining ability analysis. significant results were obtained from this experiment with good general combining parents as well as standard heterotic crosses.