Ammonia was directly synthesised from wet air at 400 °C at atmospheric pressure. A new perovskite Sm0.6Ba0.4Fe0.8Cu0.2O3−δ was used as the electrocatalyst for electrochemical synthesis of ammonia. Ammonia formation rates of 9.19 × 10−7 mol s−1 m−2 and 1.53 × 10−6 mol s−1 m−2 were obtained at 400 °C when wet air and wet N2 were introduced into a simple single chamber reactor, respectively. The perovskite catalyst is low cost compared to the previously reported Ru/MgO and Pt/C catalysts. This experiment indicates that ammonia can be directly synthesised from wet air, a very promising simple technology for sustainable synthesis of ammonia in the future.