Rice (Oryza sativa L.) is the most important cereal crop in Bangladesh and it is one of the most important staple foods in the world. The demand for rice is augmenting day by day; where the area under rice cultivation is not increasing rather it is reducing. Plant growth regulators at different concentrations can have quite different effects in different plants and sometimes the same plant growth regulator at identical concentrations can have different effects on various organs of the same plant. Naphthalene acetic acid (NAA), a synthetic growth regulator is known to affect the growth, development and other physiological and biochemical processes of a number of plants. Reports regarding the effect of NAA on rice are very limited. In this book the effects of foliar application of NAA on some physiological, biochemical and yield parameters and also on nutrient content of two varieties of rice has been reported.