The majority of plasma proteins are synthesized and secreted by the liver, the most abundant being albumin. The mechanism of its synthesis and secretion has recently been elucidated in greater detail. Synthesis of the polypeptide chain is initiated on free polyribosomes with methionine as first amino acid. The following segment of the nascent protein is rich in hydrophobic amino acids, which probably mediate the binding of albumin-synthesizing polyribosomes to the endoplasmic membrane. The albumin to be, called preproalbumin, is transferred into the intracisternal space of the rough endoplasmic reticulum. Preproalbumin is shortened to proalbumin by hydrolytic cleavage of 18 amino acids from the N-terminus. Proalbumin is transported to the Golgi apparatus. Finally, it is converted to albumin, immediately before secretion into the bloodstream, by removal of another six N-terminal amino acids. Functional implications and general relevance of the observations made with albumin will be discussed.