Optic neuritis has been described among the toxic effects of Ethambutol. This side effect is dose related. The mean duration of Ethambutol induced optic neuritis (EON) is three months. We report a case of EON after few days of exposure to Ethambutol and the symptoms resolved after discontinuation of Ethambutol. This most likely represents an idiosyncratic reaction which is different as compared to dose related optic neuritis.