Seven maize inbred lines and their 21 direct crosses produced through half-diallel scheme were evaluated with four open-pollinated varieties during kharif, 1999. General combining ability variance for all the characters was higher than specific combining ability variance except for ear height indicating the importance of additive genes in controlling these traits. Based on the estimates of their general combining ability effects, 0741 ⊗ 1-1-1-10-4-4 and Pop 31 ⊗ 18-2-1-1-4-2-2-1 to 19 were good general combiners for grain yield. Five single cross hybrids were identified as potential cross combinations on the basis of high sca effects for grain yield/ha. One hybrid, Tarun ⊗ 36-1-1-1 X Tarun ⊗ 83-1-32 depicted significant sca effects in desired direction for days to 50% taselling, 100-kernel weight, number of kernel rows/ear and grain yiele. Heterosis over mid parent, better parent and standard check variety was also estimated. The cross 0831 ⊗ 41-1-2-1 X Pop 31 ⊗ 18-2-1-1-4-2-2-1 to 19 showed highest mid parent heterosis for both grain yield (26.7%) and ear length (25.0%).