Gelatin-hydroxyphenylpropionic acid (Gtn-HPA) hydrogels are highly porous and biodegradable materials. Herein we report a fiber spinning method that can produce cell-seeded solid and hollow hydrogel fibers by enzymatically cross-linking Gtn-HPA in solutions flowing within a capillary tube. The cell-immobilized hydrogel fibers, with feature sizes down to 20 microm, are formed as a result of continuous cross-linking of cell-mixed hydrogel precursors in a multiphase laminar flow. This fiber formation process is mild enough to retain the cell viability. The continuous fiber formation, simultaneous cell encapsulation, as well as versatile combination of fiber structures provided by this approach make it a promising and effective technique for the preparation of cell-seeded hydrogel scaffolds and carriers for tissue engineering.