Consejo Superior de Investigaciones Cientificas Universidad Autonoma de Madrid (CSIC-UAM) 1 article published in JoVE Immunology and Infection Analysis of Human Natural Killer Cell Metabolism Javier Traba1,2, Thomas A. Waldmann3, Olga M. Anton3 1Cardiovascular Branch, National Heart, Lung and Blood Institute, National Institutes of Health, 2Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), 3Lymphoid Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health In this paper, we describe a method to measure glycolysis and mitochondrial respiration in primary human Natural Killer (NK) cells isolated from peripheral blood, at rest or following IL15-induced activation. The protocol described could be easily extended to primary human NK cells activated by other cytokines or soluble stimuli.