Abstract: A narrow-leaf mutant (nal(t)) was derived from Jinhui10 (Oryza sativa) treated with ethylmethane sulfonate.The mutant displayed a significant phenotype of narrow leaf, narrow and short culm, and short panicle. The leaf width was 0.99 and 1.42 cm at the seedling and heading stages, respectively, which was 76% and 74%, respectively, that of the wild type. The length of the first, second and third internodes from the top was 9.16, 6.97 and 3.57 cm, respectively, at the heading stage, which was 63%, 83% and 71%, respectively, that of the wild type, and the width of the first, second and third internodes from top was 0.31, 0.36 and 0.45 cm, respectively, which was 78%, 72% and 79%, respectively, that of the wild type. Genetic analysis showed that the narrow-leaf mutation was controlled by a major recessive nuclear gene, designated NAL(T), which was located between simple sequence repeat markers RM6869 and RM28537 on the long arm of chromosome 12, with genetic distances 3.1 and 9.0 cM, respectively.