A search for the rare two-body charmless baryonic decay B+→ pΛ¯ is performed with pp collision data, corresponding to an integrated luminosity of 3 fb−1, collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. An excess of B+→pΛ¯ candidates with respect to background expectations is seen with a statistical significance of 4.1 standard deviations, and constitutes the first evidence for this decay. The branching fraction, measured using the B+→KS 0π+ decay for normalisation,(Formula Presented.)where the first uncertainty is statistical and the second systematic.[Figure not available: see fulltext.].