Reinforced concrete columns in existing multi-storeyed buildings may need to be strengthened to enhance the performance during an earthquake. An experimental study on strengthening of columns for shear by concrete jacketing is presented in this paper. 38 rectangular beam-column specimens were tested under monotonic single point lateral loading, in the presence or absence of axial load. The parameters considered for the study are compressive strength of jacket concrete, amounts of longitudinal and transverse reinforcements, thickness of jacket and level of axial load. The test programme, specimen details, test set-up and results in terms of the influence of the variation of each parameter on the shear strength of the specimens, are discussed in this paper. © Springer India 2015. All rights reserved.