[en] Proton radioactivity from the closed neutron shell nucleus ¹⁵⁵Ta has been observed. It was produced via the p4n fusion evaporation channel using a ⁵⁸Ni beam on a ¹⁰²Pd target. The measured decay properties are E_p=1765(10) keV and t_1/2=12_-3⁺⁴ μs. Spin and parity J^π=11/2^- and a spectroscopic factor S_p^exp=0.58_-0.15^+0.20 characterize the decaying state. copyright 1999 The American Physical Society