Abstract: The current study was conducted using 105 hybrids resulted from diallel crosses of 15 early maturing maize inbred lines crossed in diallel mating system (Griffing’s Method IV, Model I) along with three standard checks evaluated using Alpha-Lattice Design with two replications during the 2011 main cropping season at Melkassa Agricultural Research Center. The objective of the study was to determine combining ability of elite early maturing maize inbred lines for grain yield and yield related traits. ANOVA showed that mean squares due to entries were highly significant for all studied traits except anthesis-silking interval, ears per plant and number of rows per ear, which indicates the existence of sufficient genetic variability and potential for selection and improvement of the traits.