Many proteins are capable of forming fibrils in vitro, suggesting that the propensity for fiber formation is a generic property of polypeptides. Pathways leading to fibril assembly, however, still remain elusive. In this research, dehydration of bovine serum albumin (BSA) solutions was found to result in spontaneous and organized formation of densely packed fibrils with the majority of proteins converted to parallel -sheets. BSA aggregation was investigated in regard to drying conditions (airflow, temperature, and humidity) and the influence of pH, presence of anions, and protein concentration. Aggregates were prepared at large scale and crosslinked to produce water-insoluble fibers with mechanical properties comparable to those of silk. Interactions between BSA and salts suggest that removing the inner water shell surrounding globular proteins leads to protein unfolding and aggregation at the water/air interface. BSA fibers can be formed into larger assemblies such as yarns, and dyed with acid dyes, thus showing great potential for future industrial-scale applications. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013