Mesoporous Ni100-xCox. alloys (0 <= x <= 100) have been fabricated by electroless deposition method using lyotropic liquid crystals (LLC) as meso-structural template and then evaluated as low-cost electrocatalysts for the hydrogen evolution reaction (HER) in alkaline medium. The mesoporous Ni-Co catalyst of 58:42 atomic ratio (Ni58Co42) manifests the highest electrocatalytic activity toward the HER, exhibiting a low onset overpotential (1) of 52 mV and a small Tafel slope of 60 mV dec(-1). In addition, this ordered mesostructured Ni58Co42 catalyst shows a long-term durability under harsh hydrogen evolution cycling test and 25 h chronoamperometry measurement. The outstanding HER electrocatalytic performance of the Ni58Co42 is mainly related to the synergetic combination of Ni and Co, as well as the enlarged exposure of catalytically active sites and improved transport of electrons and reacting agents arising from the unique ordered bicontinuous mesopores. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.