1D fibers of Bombyx mori silk fibroin (SF) and poly(l-lactide) (SF-s-PLLA) with side-by-side parallel arrangement of the two components in a single fiber made by electrospinning are presented. The side-by-side arrangement in both randomly oriented and aligned two-in-one fibers was confirmed by scanning electron and confocal laser scanning microscope studies. The molecular orientation and secondary structure of SF and PLLA were dependent on the fiber alignment and annealing conditions. The two sides retained their individual secondary structure before and after annealing without affecting each other in a significant way. The two-in-one fibers after post treatment with methanol and heat at 80 °C showed tensile strength 16.5 ± 1.4 MPa, modulus 205 ± 20.6 MPa, and an elongation at break of 53 ± 8%. Special 1D bio-composite ductile fibers of silk fibroin and poly(l-lactide) with side-by-side wrap-up morphology are made by bicomponent electrospinning. Both sides retain their individual secondary structure before and after annealing making them available in future for post-spinning modifications and applications such as compatibilizers, scaffolds for co-culture of different cells, and drug carrier with dual release-profile.