Porous silk fibroin/sodium alginate hybrid scaffolds were prepared through lyophilization method. Hybrid scaffolds were characterized for morphological and functional properties related to different mixture ratios between silk fibroin and sodium alginate. The silk fibroin/sodium alginate hybrid scaffolds showed a thin-layer structure and much more irregular rod-like structure appeared at the layer surface after adding 50% sodium alginate. The results of wide-angle X-ray diffraction and Fourier transform infrared analysis confirmed that the crystal structure of silk fibroin was not influenced by adding the different contents of sodium alginate, exhibiting the random coil structure in the hybrid scaffolds. The thermal behavior of the hybrid scaffolds exhibited major change with containing 30% sodium alginate or more. The porosity of the scaffolds varied between 92 and 94% with a favorable compressive modulus and stress. The mechanical properties results depicted the hybrid scaffolds containing 10% sodium alginate, with a porosity of 94.0 ± 0.10%, attained the highest compressive modulus and stress for 41 ± 6 and 44 ± 3 kPa, respectively. In addition, mineralization results showed hydroxyapatite crystal growing on the surface of the scaffold. This hybrid biomaterial should offer new and important options to the needs related to biomineralization and tissue engineering, in general. POLYM. ENG. SCI., 54:129–136, 2014. © 2013 Society of Plastics Engineers