Thirty new top crosses of maize were tested under full irrigation and water deficit circumstances after being crossed between ten new maize inbred lines and three testers. To evaluate the combining ability of several traits in maize, these crosses were set in an RCBD design with three replications along with two checks in both environments. Desirable mean values for 50% silking were detected for the crosses L25xM8 under normal irrigation and L21xM8 under water deficit. The most desirable mean values for grain yield plant-1 were obtained for the cross L29xM8 followed by L23xM4 under normal irrigation and L26xM4 under water shortage. For all examined traits, non-additive was more important than additive in all environments. The tester T1 (M4) was the best for days to 50% silking, chlorophyll content, and grain yield, while the line L2 exhibited the best GCA effects for 100 kernel weight and grain yield. The highest significant and negative SCA effects for days to 50% were detected for the crosses L25xM8 under normal irrigation and combined data. For grain yield, the cross L28x M4 gave the best SCA effects under E1 and L29x M8 under E2 and combined analysis. The most desirable heterosis for grain yield relative to both checks was obtained for the cross L23xM4 in the combined analysis. Also, the cross L26xM4 expressed desirable heterosis for most traits under both environments. The cross L29xM8 recorded the best heterosis values for days to 50% silking, 100-kernel weight, and grain yield under normal irrigation