Genome editing in plants has been boosted tremendously by the development of the CRISPR/Cas9 technology. This powerful tool allows substantial improvement of plant traits in addition to those provided by classical breeding. Here we demonstrate the development of virus resistance in cucumber (Cucumis sativus L.) by utilizing Cas9/sgRNA technology to disrupt the recessive eIF4E gene function. Cas9/sgRNA constructs were targeted to the N' and C' terminus of the eIF4E gene. Small deletions and SNPs were observed in the eIF4E gene targeted sites of T1 generation transformed cucumber plants, but not in putative off-target sites. Non-transgenic heterozygous eIF4E mutant plants were selected for production of non-transgenic homozygous T3 generation plants. Homozygous T3 progeny following Cas9/sgRNA that had been targeted to both eIF4E sites exhibited immunity to Cucumber vein yellowing virus (ipomovirus) infection and resistance to the potyviruses Zucchini yellow mosaic virus and Papaya ring spot mosaic virus-W. In contrast, heterozygous-mutant and non-mutant plants were highly susceptible to these viruses. For the first time, virus resistance has been developed in the cucumber crop, non-transgenically, not visibly affecting plant development, and without long-term backcrossing, via a new technology that can be expected to be applicable to a wide range of crop plants. This article is protected by copyright. All rights reserved.