This paper studies the temperature effect on the specific growth rate of the microorganisms (mu(c)) as particular aspect of the mathematical relationships between mu(c) of Thiobacillus ferrooxidans and the concentrations of substrate (ferrous iron) and product (ferric iron). Until now, there have been few studies of this relationship; also, there has been little work studying the influence of temperature on growth kinetics of this bacteria. In this paper, an extensive experimental phase has been developed, with the aim of determining with precision the influence of temperature on the maximum specific growth rate (mu(max)). The influence on the growth rate of T. ferrooxidans exerted by the initial pH of the medium and by agitation rate has also been studied.