Conductivity and magnetic circular dichroism (MCD) in the near infrared are measured inp‐type Ca‐doped yttrium iron garnet films. Two MCD components are known to arise in these films, associated with Ca2+substitution: one peaked at about &lgr;=1.2 &mgr;m, the other one at &lgr;=1.6 &mgr;m. We show that the center responsible for the &lgr;=1.6 &mgr;m component is the only one responsible for the remarkable electrical properties recently reported for these films. The other center provides charge compensation of Ca2+which is uneffective from the point of view of conduction which may be thus considerably enhanced by inhibiting formation of this center.