Solution blowing of soy protein (sp)/polymer blends was used to form monolithic nanofibers. The monolithic fibers were blown from blends of soy protein and nylon-6 in Formic Acid. The sp/nylon-6 ratio achieved in dry monolithic nanofibers formed using solution blowing of the blend was equal to 40/60. In addition, solution blowing of core-shell nanofibers was realized with soy protein being in the core and the supporting polymer in the shell. The shells were formed from either polyacrylonitrile (PAN), or nylon-6. The sp/nylon-6 ratio achieved in dry core-shell fibers was 32/68. For sp/PAN the ratio achieved in dry core-shell fibers was 29/71. The nanofibers developed in the present work contain significant amounts of soy protein and hold great potential in various applications of nonwovens.