A large number of studies revealed that adiponectin, a protein secreted specifically by adipose tissue, exhibits antiinflammatory, antiatherogenic, and antidiabetic properties. This 247-amino acid protein contains four differentiable domains and exists in five different configurations, which binds three kinds of receptors. The plasma adiponectin concentration is at amazing microgram level and the gender difference is very clear. Obese subjects showed decreased plasma level of adiponectin while exercise seems to restore it. Many researchers demonstrated that it could be a reliable biomarker for multiple diseases. However, there is controversy about its role in inflammation since its plasma concentration decreases in some inflammatory diseases and increases under some other inflammatory conditions. The signal transduction pathway is still not very clear yet. Could adiponectin be a promising drug target?