The influence of iron and silicon on the corrosion resistance of brasses used for pipeline fittings, in particular ball valves, was studied. Dezincification of brasses occurs during operation of valves because of contact with the working environment and is accompanied by a decrease in the level of mechanical and operational properties of the valve parts. Therefore, increasing the corrosion resistance of brasses by adjusting the chemical composition is an urgent task. It has been established that the dezincification depth increases from 250 to 450…500 microns with an increase in the iron content from 0.135 up to 0.634 %, and with an increase in the silicon content from 0.138 to 0.489 %, it decreases from 150 down to 25…30 microns. This means that silicon has a positive effect on the dezincification process. When 0.101…0.496% Si was introduced into the brass containing 0.64...0.65% Fe, the dezincification depth decreased from 400…450 down to 150…170 µm. Inhibition of the negative influence of iron on the dezincification process is achieved through the formation of iron silicides when silicon is introduced into the alloy.