Controllable doping of HgCdTe in concentrations low enough to be useful for electronic devices is accomplished by dissolving the desired dopant in mercury at or below the solubility limit. The mercury is then diluted with pure mercury, to lower the dopant concentration to that which will produce the desired impurity concentration in the end product. The doped mercury is then compounded according to conventional methods, to produce reproducibly doped HgCdTe of uniform composition.