Objective To evaluate the safety and efficacy of dexamethasone intravitreal implant 0.7 mg (DEX) for treatment of macular edema associated with retinal vein occlusion (RVO). Methods This study was a six-month, randomized, double-masked, sham-controlled, multicenter, phase 3 clinical trial with a 2-month open-label study extension. Patients with branch or central RVO received DEX (n=129) or sham procedure (n=130) in the study eye at baseline; all patients who met re-treatment criteria received DEX at month 6. Efficacy measures included Early Treatment Diabetic Retinopathy Study (ETDRS), best-corrected visual acuity (BCVA), and central retinal thickness (CRT) on optical coherence tomography. Results Time to ≥15-letter BCVA improvement from baseline during the first 6 months (primary endpoint) was earlier with DEX than sham (P＜0.001). At month 2 (peak effect), the percentage of patients with ≥15-letter BCVA improvement from baseline was DEX: 34.9%, sham: 11.5%; mean BCVA change from baseline was DEX: 10.6±10.4 letters, sham: 1.7±12.3 letters; and mean CRT change from baseline was DEX: −407±212 μm, sham: −62±224 μm (all P＜0.001). Outcomes were better with DEX than sham in both branch and central RVO. The most common treatment-emergent adverse event was in-creased intraocular pressure (IOP). Increase sin IOP generally were controlled with topical medication. Mean IOP normalized by month 4, and no patient required incisional glaucoma surgery. Conclusions DEX had a favorable safety profile and provided clinically significant benefit in a Chinese patient population with RVO. Visual and anatomic outcomes were improved with DEX relative to sham for 3 - 4 months after a single implant.