Experiments were conducted at the experimental farm of Rice Research and TrainingCenter, Sakha in 2004 and 2005 to evaluate the effect of nitrogen fertilizer sources as farmyard manure FYM and / or urea at different rates on rice blast, white tip nematode and rice stem borer on seven rice cvs. The considered cultivars were Giza 171, Giza 176, Giza 177, Giza 178, Giza 181, Skha 101 ans Sakha 104 fertilized with 30m³ FYM, 20 M³ FYM, 10 m³ FYM + 20 kg N urea, 40 kg N urea, 60 kg N urea and 80 kg N urea/fed. Results showed that leaf and panicle blast infection was not observed on Giza 177, Giza 178 and Giza 181 while Giza 171 had the highest infection followed by Giza 176, Sakha 104 and Sakha 101. Blast isolate obtained from Sakha 104 cv. was identified as IB 45, while that obtained from Sakha 101 cv. was identified as IG1. White tip nematode was affected by kind and amount of nitrogen application. The highest infection was detected on Giza 171 followed by Giza 177 and Sakha 101, while Giza 176, Giza 178 and Giza 181 were the lowest infected cultivars, whereas no infection was found on Sakha 104. High rates of organic or inorganic nitrogen led to an increase in susceptibility of cultivars to white tip nematode. The rice stem borer infestation was highest at the highest rate of mineral nitrogen (80 kg / fed), followed by 60 kg N / fed or application of 30 ton FYM / fed. The lower rates of mineral nitrogen (40 kg / fed) resulted in less borer infestation.