Alginate/chitosan polyelectrolyte complex (PEC) hybrid fibers are promising materials for scaffold-making in tissue engineering. In this study, a new method termed "hydro-spinning" was developed to make alginate/chitosan hybrid fibers. In hydro-spinning, a chitosan solution was pumped into a flowing sodium alginate solution and sheared into streamlines. These elongated streamlines subsequently transformed into alginate/chitosan PEC ribbon-like fibers before breaking up into pieces. Average diameter and chitosan content of the fibers correlated positively with the chitosan concentration used in spinning. These hybrid fibers showed a high water-absorbability of around 50-fold to 60-fold of water to their dry weight and could retain their integrity after saturation in minimum essential medium (MEM) medium for 30 days. In vitro culture experiments demonstrated that these fibers were able to support the three-dimensional growth of MCF-7, suggesting the potential applications of these fibers in biomedical and bioengineering fields such as tissue engineering.