PURPOSE: To determine the frequency and type of imaging artifacts in the optic nerve head (ONH) analysis protocol of the optical coherence tomograph (Stratus OCT) in healthy and glaucomatous eyes. DESIGN: Retrospective study. METHODS: Two experienced operators reviewed imaging obtained in 264 eyes from 264 participants (146 controls, 118 glaucoma patients). Each participant had a minimum of 3 scans using fast ONH protocol. Only scans with good quality were included in the study. RESULTS: Thirty-two eyes (12%) had imaging artifacts in at least one of the radial scans distributed as follows: 12 eyes showed incorrect identification of vitreous-retinal surface plane, 3 eyes had incorrect positioning of retinal pigment epithelium-choriocapillaris border reference points, 10 eyes had vitreous tuft and/or remnants of posterior hyaloid artery above the optic disk that were mistakenly included in the estimation of optic disk parameters (rim and cup area), and 7 eyes with small optic disk were reported with rim area of 0 because of erroneous placement of reference planes. CONCLUSIONS: In the Stratus OCT ONH protocol, careful inspection of each of the 6 radial scans is needed, as artifacts may be present in any of these scans. For the most common artifact found, modifications on retinal sensitivity may be successful in correcting such errors. © 2009 Lippincott Williams & Wilkins, Inc.