Abstract The Letter is devoted to studies of prospects to search for hypothetical W ′ gauge bosons at hadron colliders via single-top quark production process. A special attention is paid to the interference between the Standard Model (SM) W and W ′ boson contributions. A model independent analysis is performed for a wide interval of W ′ masses potentially acceptable for a detection at the Tevatron and LHC. It is shown that the interference contribution to the cross section of the most promising s-channel single-top production mode could be as large as 30% for certain parameter points which is comparable to NLO effects computed in previous studies separately for the W ′ signal and the SM single-top background. The interference contribution affects particle distributions and has to be taken into account for more accurate W ′ signal and background simulation.