Epitaxial Y3Fe5O12 films were grown on (111) gadolinium gallium garnet substrates using the pulsed laser deposition technique. The results demonstrated that epitaxial YIG films could be prepared under a wide range of deposition conditions, but narrow linewidth (DELTAH congruent-to 1 Oe) films were produced only at low oxygen partial pressures and relatively high substrate temperatures. In addition, the films exhibited a uniaxial magnetic anisotropy parameter which changed sign from negative to positive with increasing oxygen partial pressure.