The crystal growth of pyrite in aqueous supersaturated solutions at pH 6.50, 25 degrees C was investigated using the seeded growth, pH-stat technique. Crystal growth started immediately after inoculation of iron(II) sulfide supersaturated solutions with pyrite seed crystals. The crystal growth rates measured from the desupersaturation curves were found to depend strongly on the relative solution supersaturation with respect to pyrite. Kinetics analysis yielded an apparent order of 3.5 +/- 0.5 suggesting a surface diffusion controlled mechanism. The presence of organophosphorus compounds such as 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), N,N,N＇,N＇-ethylenediaminetetrakis(methylenephosphonic acid)(ENTMP) in the supersaturated solutions at concentration levels between 0.1 and 1000 nM inhibited the crystal growth of pyrite by 70-100% with respect to the blank experiments. Moreover, in the presence of the compounds tested the crystal growth of pyrite was preceded by well-defined induction times which increased sharply with inhibitor concentration. At concentration levels as low as 1 mM, crystal growth was completely suppressed. The presence of nitrilotris(methylenephosphonic acid) (NTMP) had no inhibition effect on pyrite crystal growth. The influence of the inhibitors tested on the kinetics of crystal growth was attributed to the blocking of the active growth sites due to adsorption.