Measurements of superconducting energy gap on BCC molybdenum-rhenium Mo-Re alloys with 10,15, 20 and 25% Re have been performed by tunnelling for the first time. In this experience we have found a particularly strong increase of Tc between 10 an 15% Re, which is not, however, followed by a corresponding increase of the energy gap ; this is reflected in an anormalous decrease of 2Δo/kBTc near these concentrations