The rice leaffolder (Cnaphalocrocis medinalis (Guenee) (RLF) is a destructive and widespread insect pest throughout the rice areas in Asia. The genetics of resistance to RLF in rice is very complex and not explored. This book aimed to study the quantitative trait loci associated with RLF resistance involving recombinant iInbred lines (RILs) of IR36/TNAULFR831311, microsatellite markers and various phenotypic parameters associated with RLF resistance in rice. RILs were phenotyped for assessing their level of resistance to RLF based on the leaf area damage of plants in greenhouse screening, per cent area damage by larva in the leaf bit fed (leaf bit bioassay method), length of the flag leaf and width of the flag leaf. The F8 RILs exhibited wider variation with transgressive segregation for all the traits studied. Correlation analysis revealed that damage based on greenhouse screening was significantly positively correlated with length and width of the flag leaf. Interval mapping detected three QTLs on chromosomes 1 and 7. The putative SSR markers associated with leaffolder resistance may serve as starting point to understand the genetic architecture of leaffolder resistance in rice.