Leaf structure is one of the important agronomic traits. A rolled leaf mutant was induced from an ethyl methane sulfonate (EMS)-treated japonica rice, 'Koshihikari'. The rolled leaf mutant showed phenotypes of reduced leaf width and leaf rolling. In addition, several abnormal morphological characteristics were observed, including dwarfism, defected panicle, delayed germination, and lower seed-setting. Microscopic analysis revealed that the number of small veins was decreased and the sizes of adaxial bulliform cells were reduced in the mutant leaves. The genetic study with two F2 populations from the crosses of the rolled leaf mutant with 'Koshihikari' and Milyang23 suggested that the mutant phenotype might be controlled by a single dominant gene.