Albumin is quantitatively the most important plasma protein. Albumin is a major factor for the maintenance of intravascular oncotic pressure; it also plays a significant role in the transport of exogenous or endogenous substances. Serum albumin is synthesized at a high rate in the liver. This synthetic process is modified by many interrelated factors. Oncotic pressure, malnutrition, toxins and trauma may reduce albumin production or secretion. Hormones regulate synthesis and degradation. Albumin is widely distributed, however the concentration in the extravascular space is low, compared to that in the plasma or lymph. While considerable data are available concerning albumin synthesis, little is known about degradation and further studies are required.