Rice, Oryza sativa L. is a vital food crop for more half of the global population. Unfortunately, it is subjected to attacks of several insect pests, from which is the rice stem borer, Chilo agamemnon Bles, the key insect pest species in Egypt. Monitoring population fluctuation of the insect during 2013 and 2014 rice seasons revealed the peaks of immature stages, as well as dead heart and white symptoms. In both seasons, the larvae exhibited three peaks of abundance, with high population density during August and September. The same trend, two peaks of abundance, was recorded for dead hearts. High population densities of white heads were detected in August and September with distinct peaks by late August and late September. Evaluation of varietal resistance to the borer revealed that Egyptian Jasmine cultivar was susceptible to C. agamemnon, while three cultivars were moderately susceptible; Giza 178, Giza 181 and Giza 182. Both Sakha 101 and Sakha 104 proved to be resistant to the borer throughout the three seasons. Six cultivars exhibited moderate resistance; Giza 177, Giza 179, Sakha 102, Sakha 103, Sakha 105 and Sakha 106.