A combination of cell-free biochemical and morphological studies has revealed that a coated bud-coated vesicle transport system shuttles newly synthesized proteins through the successive processing compartments of the Golgi apparatus. These "Golgi coated vesicles" operate in a manner formally analogous to the clathrin coated pitcoated vesicle system responsible for receptor-mediated endocytosis; however Golgi coated vesicles do not contain clathrin.