Arabidopsis E3 ligase salt- and drought-induced RING-finger 1 (SDIR1) has been found to be involved in abscisic acid (ABA)-related stress signaling. SDIR1-overexpressing Arabidopsis plants exhibit improved tolerance to drought. Tobacco (Nicotiana tabacum) and rice (Oryza sativa) are two important agronomic crop plants. To determine whether SDIR1 enhances drought resistance in crop plants, SDIR1 transgenic tobacco and rice plants were generated. Ectopic expression of SDIR1 in both plants conferred improved drought tolerance ability. These results suggest that SDIR1 can function as a drought-tolerance gene in both dicotyledons and monocotyledons, and that it can serve as a drought-tolerance engineering candidate gene in crop plants.