Concern has been raised with regard to some of the data of the Chinese Medical Journal article titled, “microRNA-218 Inhibits Oxygen-induced Retinal Neovascularization via Reducing the Expression of Roundabout 1,” published in pages 709-715, issue 6, vol. 129, 2016.[1] These data were redundant with another article published in Int J Mol Med 37: 1139-1145, 2016; doi: 10.3892/ijmm.2016.2511, which had been retracted.This Expression of Concern should not be considered as a statement regarding the validity of the work, but rather as a notification to readers.