The development of highly active non-Pt electrocatalysts with superior stability for the hydrogen evolution reaction (HER) remains a great challenge. Herein, we report CoNi2S4 nanoparticles synthesized by a facile one-pot hydrothermal method as highly efficient electrocatalysts for the HER in strongly alkaline electrolyte for the first time, and the effect of preparation temperature was also discussed systematically. These as-prepared catalysts exhibited superior HER activity compared to other non-noble metal catalysts and the catalyst obtained at 220 degrees C showed the best activity with the smallest Tafel slope of 85 mV dec(-1) and good stability in 1.0 M KOH, making it a promising candidate to replace Pt based catalysts. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.