The most significant physiological effect of exogenous gibberellic acid (GA3) on plants is to break dwarfism and stimulate the elongation of genetically dwarf genotypes, as these dwarf lines generally have a low level of endogenous GA3 in their tissues (Singh et al 1978, Suge 1990). However, the same effects have not always been noted in all cases. Several dwarf genotypes of rice and wheat do not respond to exogenous application of GA3 mainly because their tissues have high endogenous GA3 (Singh et al 1981, Kumar et al 1992). The GA3- induced elongation in dwarf genotypes is mainly attributed to greater cellular, biochemical, and physiological activities of the plants. This study looked at the biochemical effects of exogenous GA3 on morphologically GA3-responding and nonresponding rice genotypes.