The ferrous sulphate, which is a waste product in titanium white production at the Chemical Plant "Police" S.A., was subjected to microbiological oxidation with Thiobacillus ferrooxidans bacteria. The kinetic parameters of the culture growth were calculated on the basis of the Monod equation. The process was found to be best described by the model of the autocatalytic 1st order reaction with respect to the product and 1st order reaction with respect to the substrate. The effect of temperature and pH on the course of the process was studied. The kinetics of oxidation of ferrous ions coming from the waste ferrous sulphate was studied in the process with laboratory bacteria strain as well as the strain adapted to the waste product and compared with that of pure substrate oxidation. Analysis of the precipitates formed during microbiological oxidation of the waste ferrous sulphate proved that (NH₄)Fe₃(SO₄)₂(OH)₆ with the admixture of NaFe₃(SO₄)₂(OH)₆ and KFe₃(SO₄)₂(OH)₆ are formed.