An isolated oculomotor nerve palsy is very rarely the presenting sign of a pituitary adenoma. It may occur slowly due to mechanical compression or rapidly, secondary to pituitary apoplexy. Magnetic resonance imaging (MRI) with and without gadolinium DTPA enhancement provides excellent anatomical detail and is useful in the planning of the operative procedure. When correctly diagnosed and treated, the third nerve dysfunction appears to be reversible. We report a case of a pituitary adenoma presenting with an isolated, partial oculomotor nerve palsy in the setting of apoplexy. The pathophysiology, prognostic factors and MRI findings of this entity are discussed.