In order to identify resistance genes for bacterial leaf blight in some selected rice cultivars, Toyonishiki, Milyang 23 IR 24 and Cas 209, and their hybrids were subjected to test with new isolates of the pathogen. Toyonishiki was resistant to the two Myanmar isolates, BM8417 and BM8429 and susceptible to the Japanese isolate H8584. Milyang 23 and IR 24 were resistant to all these isolates. Cas 209 was resistant to the Japanese isolate, but susceptible to the Myanmar isolates. The F₂ analysis indicates that Milyang 23 and IR 24 have two dominant genes, consisting of one for resistance to the Myanmar isolates and the other for resistance to the Japanese isolate. Toyonishiki, Milyang 23 and IR 24 share a dominant gene for resistance to the Myanmar isolates. Cas 209 has a dominant gene identical to that of Milyang 23 and IR 24. This gene, apart from another gene of Xa-10, controls resistance to H8584, a Japanese isolate. This resistance gene conveyed by Milyang 23, IR 24 and Cas 209 might be identical to that of Te-tep identified by Noda and Ohuchi. The gene in Toyonishiki, Milyang 23 and IR 24 for resistance to the Myanmar isolates is recognized as a new resistance gene. It was designated as Xa-18 by the Rice Genetic Cooperative.