ABSTRACT: Importance:Ranibizumab is a viable treatment option for eyes with proliferative diabetic retinopathy (PDR) through 2 years. However, longer-term results are needed. Objective:To evaluate efficacy and safety of 0.5-mg intravitreous ranibizumab vs panretinal photocoagulation (PRP) over 5 years for PDR. Design, Setting, and Participants:Diabetic Retinopathy Clinical Research Network multicenter randomized clinical trial evaluated 394 study eyes with PDR enrolled February through December 2012. Analysis began in January 2018. Interventions:Eyes were randomly assigned to receive intravitreous ranibizumab (n?=?191) or PRP (n?=?203). Frequency of ranibizumab was based on a protocol-specified retreatment algorithm. Diabetic macular edema could be managed with ranibizumab in either group. Main Outcomes and Measures:Mean change in visual acuity (intention-to-treat analysis) was the main outcome. Secondary outcomes included peripheral visual field loss, development of vision-impairing diabetic macular edema, and ocular and systemic safety. Results:The 5-year visit was completed by 184 of 277 participants (66% excluding deaths). Of 305 enrolled participants, the mean (SD) age was 52 (12) years, 135 (44%) were women, and 160 (52%) were white. For the ranibizumab and PRP groups, the mean (SD) number of injections over 5 years was 19.2?(10.9) and 5.4?(7.9), respectively; the mean (SD) change in visual acuity letter score was 3.1?(14.3) and 3.0?(10.5) letters, respectively (adjusted difference,?0.6; 95% CI, -2.3 to 3.5; P?=?.68); the mean visual acuity was 20/25 (approximate?Snellen equivalent) in both groups at 5 years. The mean (SD) change in cumulative visual field total point score was -330?(645) vs -527?(635) dB in the ranibizumab (n?=?41) and PRP (n?=?38) groups, respectively (adjusted difference,?208 dB; 95% CI, 9-408). Vision-impairing diabetic macular edema developed in 27 and 53 eyes in the ranibizumab and PRP groups, respectively (cumulative probabilities: 22% vs 38%; hazard ratio,?0.4; 95% CI, 0.3-0.7). No statistically significant differences between groups in major systemic adverse event rates were identified. Conclusions and Relevance:Although loss to follow-up was relatively high, visual acuity in most study eyes that completed follow-up was very good at 5 years and was similar in both groups. Severe vision loss or serious PDR complications were uncommon with PRP or ranibizumab; however, the ranibizumab group had lower rates of developing vision-impairing diabetic macular edema and less visual field loss. Patient-specific factors, including anticipated visit compliance, cost, and frequency of visits, should be considered when choosing treatment for patients with PDR. These findings support either anti-vascular endothelial growth factor therapy or PRP as viable treatments for patients with PDR. Trial Registration:ClinicalTrials.gov Identifier: NCT01489189.