The purpose of this study was to report a patient with acute zonal occult outer retinopathy (AZOOR) unilaterally, who received steroid pulse therapy. A 42-year-old woman presented with photopsias and severe vision loss in her left eye. Visual acuity was 0.04, and Humphrey visual field testing showed overall depression with a mean deviation (MD) value of -25.78 dB in the left eye. Fundus and angiographic examinations found no specific abnormal findings, leading to a diagnosis of AZOOR. Optical coherence tomography showed attenuation of the photoreceptor inner segment/outer segment junction (IS/OS) line. Focal macular electroretinography (fmERG) demonstrated that there were non-detectable responses at 5°, 10° and 15° (in diameter). Following steroid pulse therapy, her visual acuity was 1.0, her MD value improved to -16.08 dB, and there were both partial recovery of the IS/OS line and apparent improvements of fmERG responses (at 10° and 15°). The present findings suggest that steroid pulse therapy might potentially be an effective treatment in some AZOOR patients.