Three cases of mucormycosis, two in diabetics and one in an intravenous drug abuse patient, are presented. Magnetic resonance imaging proved to be useful in all cases, as was computed tomography. In one case, extremely low signal was detected from the fungal mass. It is surmised that this appearance was a result of high concentrations of iron and manganese. The low-signal area simulated air in paranasal sinuses; however, CT displayed a mildly enhancing soft tissue mass and allowed the correct diagnosis to be made. In another patient, pontine infarction was demonstrated by MR. In the third case the MR findings of mucormycosis involving the basal ganglia are shown and correlated with CT. Subsequent imaging studies demonstrated reduction of the mass, corresponding to clinical improvement.