[en] Engineering current densities and tensile strain effects in filamentary MgB₂ wires manufactured by the diffusion of magnesium into boron (IMD) process have been examined at a 4.2 K and with an external field of 6–7.5 T. MgB₂ wires with 6 or 7 filaments, Nb or Ti barriers and Monel^®, GlidCop^® and HITEMAL^® outer sheaths were examined and compared with commercially produced MgB₂ conductors. IMD wires allow for higher engineering current densities in comparison to commercial wires produced by the powder-in-tube (PIT) process, but a uniform Mg/B ratio in the as-formed IMD wires is extremely important for long-length homogeneity. IMD and PIT wire samples were loaded progressively to determine the irreversible strain limit (ε _irr) and stress limit (σ _irr) defined as the maximum loaded strain or stress where the critical current (I _c) is still reversible. It was found that the strain tolerances of the tested MgB₂ wires are affected by the metallic components used. The wire with the lowest content of metallic elements (Nb/Monel^®) led to the lowest strain tolerance (ε _irr = 0.30%). Alternately, the wire with stronger GlidCop^®/Monel^® sheath resulted in the best strain tolerance (ε _irr > 0.50%). (paper)