THE MAIN objectives of the present study was to estimate the combining ability for some new white maize inbred lines under different environmental conditions and evaluation the 21 F₁ crosses come from this study under two plant densities (D₁ and D₂) at two locations (L₁ and L₂). Obtained results could be summarized as follows: The non-additive genetic effects was more important than additive genetic effects in the inheritance of this traits; grain yield at L₁D₁, L₁D₂, L₂D₂ and combined data, days to 50% silking at all environments and combined data, ear height at L₁D₂ and 100-kernel weight at L₁D_1. The additive gene effects were most responsible for controlling the inheritance of this traits; for grain yield at L₂D₁, plant height under all environments and combined data, ear height at L₁D₁, L₂D₁, L₂D₂ and combined data and 100-kernel weight at L₁D₂, L₂D₁, L₂D₂ and combined data. The inbred lines; P₁ at L₂D₁, P₄ at L₁D₂ and P₇ at L₁D₂ had positive and significant GCA effects for grain yield. The single crosses; (P₁xP ₄), (P₂ x P₆), (P₂ x P₇), (P₄ x P₇) and (P₅ x P₇) were the best crosses for superiority relative to SC10 for grain yield.