The disintegration scheme of Eu 156 has been studied using the Chalk River high-resolution β-ray spectrometer, scintillation spectrometers and coincidence techniques. The internal conversion electron spectrum was studied at momentum resolution settings in the range 0.02–0.08%. Conversion lines were observed corresponding to 28 γ-transitions in Gd 156 of energies in keV: 88.97 (E2), 199.19 (E2), 599.5 (E1), 646.3 (E1), 709.9, 723.5, 811.8 (M1), 865.8, 867.1 (E1), 960.8 (E1), 1040.5, 1049.5, 1065.1 (E2), 1079.2, 1153.4 (E1), 1154.0 (E2), 1168.5, 1230.7 (E1), 1242.4 (E1), 1277.4, 1366.4 (E1), 1876.8 (M1, E2), 1937.5 (M1, E2), 1965.8 (M1, E2), 2026.4 (M1, E2), 2097.8 (M1, E2), 2181.0 (M1, E2) and 2186.8 (M1, E2). The multipolarity assignments for the two lowest energy transitions were deduced from the L sub-shell conversion line intensity ratios; the others are based on the K-conversion coefficients deduced in this work. The β-ray spectrum of Eu 156 has at least four components of energies 2430±10 keV (33%), 1195±15 keV (14%), 485±20 keV (36%) and a low energy component of < 350 keV (≈ 17%). A β-γ coincidence experiment shows that the 2430 keV component feeds the ground state of Gd 156. Considerations of gamma-ray energy sums and γ-γ coincidence experiments establish levels in Gd 156 at energies in keV of 0(0+), 88.97 (2+1), 288.16 (4+), 1154.0 (2+) 1242.4 (1−), 1319.7, (2−), 1366.4 (1−) 1965.8 (1,2+), 2026.4 (1,2+), 2181.0 (1, 2+) 2186.8 (1, 2+) and 2203.4 (0, 1, 2+). Most of the low spin levels in Gd 156 which are fed in the β-decay of Eu 156 (0) were not observed in the electron capture decay of Tb 156(3, 4−).