A method of producing human serum albumin (HSA) in monocot plant seeds, by transforming a monocot plant cell with a chimeric gene containing a promoter from the gene of a maturation-specific monocot plant storage protein, a first DNA sequence operably linked to the promoter and encoding a signal sequence, and a second DNA sequence linked in translation frame with the first DNA sequence and encoding HSA, where the first DNA sequence and the second DNA sequence together encode a fusion protein containing an N-terminal signal sequence and the HSA; growing a monocot plant from the transformed monocot plant cell for a time sufficient to produce seeds containing the HSA; and harvesting the seeds from the plant.