AIM: To determine the incidence and predictive factors for epiretinal membrane (ERM) formation in eyes with complicated primary rhegmatogenous retinal detachment (RRD) tamponaded with silicone oil (SO). METHODS: This retrospective case-control study included 141 consecutive patients with (51 eyes) and without (90 eyes) ERM formation after primary pars plana vitrectomy (PPV) and SO tamponade for complicated RRD. The risk factors for ERM were assessed using logistic regression analysis. RESULTS: The prevalence of postoperative ERM was 36.2% (51/141). Multivariate logistic regression analysis showed that the risk factors for ERM in SO-tamponaded eyes included preoperative proliferative vitreoretinopathy [PVR; odds ratio (OR), 2.578; 95% confidence interval (CI) 1.580–4.205, P<0.001], preoperative choroidal detachment (OR, 4.454; 95%CI 1.369–14.498, P=0.013), and photocoagulation energy (OR, 2.700; 95%CI 1.047–6.962, P=0.040). The duration of the preoperative symptoms, intraocular SO tamponade time, giant retinal tear, preoperative vitreous hemorrhage, preoperative best-corrected visual acuity, number of breaks, quadrants of RRD, axial length, and photocoagulation points were not predictive factors for ERM formation. CONCLUSION: Preoperative PVR, choroidal detachment, and photocoagulation energy are risk factors of ERM formation after complicated RRD repair. Better ophthalmic care as well as patient education are necessary for such patients with risk factors.