Iron toxicity (Fe) is a major problem in acid sulfate rice soils in the tropics. It is a physiologically complex nutrient disorder and deficiency in several other nutrients-especially P, K, Mg, and Zn-has been shown to play a major role in its occurrence (Sahu 2001). Iron toxicity is caused by excess uptake of Fe and is controlled by various factors such as genetic tolerance, active Fe content, soil nutritional status, and soil reaction rather than by total Fe content. Deficiencies in Ca, Mg, and Mn are rarely observed in lowland rice, but those in P, K, and Zn deserve special attention in order to reduce Fe toxicity (Sahwarat 2000). Hence, to manage Fe toxicity, an integrated approach involving the use of Fe-tolerant rice varieties, soil and water management, and plant nutrition is more appropriate. This study aimed to determine the effects of the integration of genetic tolerance (by selecting varieties that vary in tolerance) with nutrition (through different levels of fertilizers and lime) on iron toxicity and its influence on rice yield in low-lying acid sulfate rice soils of Kuttanad, Kerala, India.