An extremely rare case of a thalamic hydatid cyst is presented and the literature is reviewed. A right thalamic hydatid cyst without rim enhancement or perifocal edema was detected by computed tomography and magnetic resonance. This lesion was extirpated successfully with intact contents via contralateral transcallosal approach. To our knowledge, this is the second hydatid cyst of the thalamus, an unusual location, and the first hydatid cyst to be removed completely with intact contents reported in the literature. Copyright (C) 1999 S. Karger AG, Basel.