Obesity increases the risk for metabolic, cardiovascular, chronic inflammatory, and several malignant diseases and, therefore, may contribute to shortened lifespan. Adipokines are peptides that signal the functional status of adipose tissue to targets in the brain, liver, pancreas, immune system, vasculature, muscle, and other tissues. Secretion of adipokines, including leptin, adiponectin, fibroblast growth factor 21 (FGF21), retinol-binding protein 4 (RBP4), dipeptidyl peptidase 4 (DPP-4), bone morphogenetic protein (BMP)-4, BMP-7, vaspin, apelin, and progranulin, is altered in adipose tissue dysfunction and may contribute to a spectrum of obesity-associated diseases. Adipokines are promising candidates both for novel pharmacological treatment strategies and as diagnostic tools, provided that we can develop a better understanding of the function and molecular targets of the more recently discovered adipokines.