When a beam flange is coped to allow clearance at the connection, the strength of the coped region will be reduced. Local web buckling at the coped region may occur when the cope length is long and/or the compression flange is braced. Experimental and analytical investigation of the strength of coped steel I beams were conducted by a number of researchers and design formula was also proposed. However, the proposed formula underestimates the local web buckling capacity of a coped I beam, especially when the cope-depth to beam-depth ratio is small. To improve this discrepancy, full-scale tests of the web buckling strength of coped steel I beams and a series of analytical studies were carried out. A modified plate buckling formula, which considers the shear buckling phenomenon at the coped region, is proposed. The modified formula gives a better prediction of the local web buckling strength of a coped I beam. The test-to-predicted ratios varies from 0.92 to 1.06.