The 2,2′-bipyridine effects on iron monosulfide (FeS) oxidative dissolution rates have been examined by potentiodynamic polarization and electrochemical impedance spectroscopy. The adsorption of 2,2′-bipyridine to synthetic FeS was investigated by batch adsorption experiments, SEM, energy-dispersive X-ray analysis and Raman spectroscopy. The experiments were performed in air-saturated solutions at pH 5, 25 °C and an ionic strength of I = 0.004 M NaCl. Correlation between oxidative dissolution rates and 2,2′-bipyridine adsorption suggests that FeS oxidative dissolution is the result of two antagonistic processes: (i) the inhibiting adsorption of 2,2′-bipyridine on mineral surface and (ii) the promoting effect of 2,2′-bipyridine on the iron dissolution from FeS surface. Copyright © 2014 John Wiley & Sons, Ltd.