A plasmid for a yeast host, the plasmid comprising in sequence: (1) a yeast derived promoter, (2) an albumin-encoding region placed under control of the yeast-derived promoter, (3) a transcription terminator and (4) a sequence homologous to a part of the yeast host chromosomal sequence such that the plasmid is capable of being integrated into the yeast host cell chromosome and wherein the plasmid is incapable of autonomous replication in yeast cells; a yeast host transformed with the above plasmid; a method of producing a yeast transformant which comprises transforming a yeast host by integrating at least two different plasmids each having a sequence homologous to a part of the host yeast chromosomal sequence one at a time into the chromosome of the yeast host cell; and a method of producing albumin which comprises cultivating the above transformant and recovering the thus-produced albumin.