The impact of heat treatment on the performance of various polymers as ferric ions stabilization agents in an aqueous system at pH 7.00, 23 °C has been investigated. The polymers evaluated include: (a) homo-polymers of acrylic acid, methacrylic acid, maleic acid, 2-acrylamido-2-methylpropane sulfonic acid, sulfonated styrene; (b) co-polymers of acrylic acid: 2-acrylamido-2-methylpropane sulfonic acid and maleic acid: sulfonated styrene, and (c) ter-polymers of acrylic acid: 2-acryalamido-2-methylpropane sulfonic acid: sulfonated styrene, acrylic acid: methacrylic acid: t-butylacrylamide, and acrylic acid: 2-acrylamido-2-methylpropane sulfonic acid: t-butylacrylamide. It has been found that all polymers lose performance to a varying degree when exposed to thermal treatment (150 °C, 200 °C, 240 °C, 20 hr). The performance data collected before and after thermal treatment suggest that sulfonated styrene containing co- and ter-polymers are better ferric ions stabilization agents than the co- and ter-polymers containing 2-acrylamido-2-methylpropane sulfonic acid and t-butylacrylamide. In addition, it has been found that heat treatment exhibits positive influence on the performance of homo-polymer of 2-acrylamido-2-methypropane sulfonic acid. The results have been explained in terms of loss of 2-acrylamido-2-methylpropane sulfonic acid and t-butylacrylamide in the co- and ter-polymers during thermal treatment.