Slow release technique is a new trial to control the release of manganese and iron ions from styrene-butadiene rubber (SBR) formulations containing manganese and iron chlorides. The SBR compounded was mixed and vulcanized according to the general equipment of rubber. Discs of surface area about 1.6 cm(2) for each one were prepared and subjected to leaching rate test in aqueous media. The release rate of manganese and iron ions was prolonged for up to 5 months. The profile behavior of the release for the two investigated ions are similar, the difference between them is in the amount of release dispersed ions in water. The concentration of active ingredients; manganese and iron chlorides; and environmental water temperature were affected on the amount of release rate. According to the higher Solubility of manganese chloride on aqueous media, the release of manganese was greater than iron. The diffusions coefficient of the released manganese and iron ions in aqueous media were 7.9 x 10(-7) and 4.9 X 10(-7), to Higuch's respectively, according equation. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 811-817, 2009