Therapeutic biologics/proteins have attracted extensive attention in biomedical application. Proteins participate in a variety of vital processes in the body and are therefore used as therapeutic agents in the treatment of miscellaneous human diseases including cancer therapy, vaccination and autoimmune diseases. However, design of novel drug delivery systems to achieve a non-toxic, constant and efficient delivery with minimal doses of therapeutic biologics is still challenging. In this study we have successfully demonstrated the potential of recombinant spider silk-based eADF4(C16) hydrogels as injectable protein depots. Hydrogels made of the recombinant spider silk protein eADF4(C16) were used to encapsulate the model biologicals BSA, HRP and LYS by direct loading or through diffusion, and their release was studied. Release of model biologicals (BSA and HRP) from eADF4(C16) hydrogels was fast (finished within a day) in case no electrostatic interaction between the biological and the silk protein was obtained. However, release of model biologicals (LYS) electrostatically interacting with the silk hydrogels showed much prolonged release (several hours up to few days). To further extend the biological release, spider silk particles were loaded with biologicals and implemented in eADF4(C16) hydrogels. Furthermore, the release profile could be modestly controlled by varying the pore sizes of eADF4(C16) hydrogels. Overall, these results lay the foundation for eADF4(C16) hydrogel and hydrogel–particle composites as injectable systems for delivering therapeutic biologics.