The term junctional scotoma of Traquair is used to describe a unilateral temporal visual field defect due to pathology of the ipsilateral optic nerve where it joins the chiasm. We report a 26-year-old woman who presented with blurred vision of her left eye. Examination revealed visual acuity of 20/20 OU, AO-HRR color plates 6/6 OD and 4.5/6 OS, and a 0.3 log unit relative afferent pupillary defect on the left side. Computer and Goldmann perimetry revealed a normal visual field OD and a paracentral temporal scotoma OS. Magnetic resonance imaging scan disclosed a sellar mass, expanding mainly into the left suprasellar area. Laboratory findings and pathological studies were consistent with a prolactin-secreting pituitary adenoma. While involvement of the temporal visual field in only one eye (junctional scotoma of Traquair) is found in about 10% of patients with pituitary adenoma, involvement of only the paracentral temporal visual field in one eye is rare (1–2%). Recognition of this rare syndrome is important because careful visual field analysis discloses a vertical step and helps to avoid misdiagnosing optic neuritis.