This experiment was conducted at Experimental Farm of Rice Research Department at Sakha Agriculture Research Station, Sakha, Kafr EL Sheikh, Egypt during 2014 and 2015 rice growing seasons to study the effect of seedling ages and nitrogen rates on the productivity of two Egyptian hybrids combinations, Egyptian hybrid 1 and new hybrid combination SK2151 H on different characters. A split split-plot design with three replications was used. The main plot was devoted to hybrid rice combinations, while the seedling age were arranged in the sub plots and nitrogen rates were assigned in the sub–sub plots with three replications.  Four rates of nitrogen (zero, 55, 110 and 165 kg N/ha) and three seedling ages (20, 25 and 30 days), were used, The date of sowing was at 1^st May of each season. The data were recorded on plant height (cm), panicles hill^-1, panicle weight (g), panicle length (cm), grain yield (tha^-1), 1000-grain weight (g), harvest index (%) and spikelet fertility %. Results showed that, the high rate of nitrogen significantly influenced on plant height (cm),panicles hill^-1, panicle weight(g), panicle length (cm), grain yield (tha^-1), 1000-grain weight (g), harvest index (%) and spikelet fertility (%), The highest grain yield (13.600 tha^-1) resulted from 20 days seedling age and  165 kg nitrogen per hectare for the Egyptian hybrid 1  in the second season. While, the lowest grain yield (4.230 tha^-1) was recorded without application of nitrogen fertilizer (control) with seedling age of 30 days for SK 2151H in the first season.