Polyelectrolyte complex (PEC) beads were prepared from water-soluble chitosan (WSC) and alginate complex solution with different ratios by dropping method, and all procedures used were performed in aqueous medium at neutral environment. The structure and morphology of the beads were characterized by IR spectroscopy and scanning electron microscopy (SEM). IR spectroscopy confirmed the electrostatic interactions between amino groups of WSC and carboxyl groups of alginate. SEM showed internal section of the PEC bead, which had porous structure compared with compact structure of alginate beads. The swelling behavior, encapsulation efficiency, and release behavior of bovine serum albumin (BSA) from the beads at different pHs were investigated. PEC beads demonstrated different responses to pH from alginate beads. The ratio of WSC to alginate influenced the encapsulation and release of BSA. At pH 1.2, small amount (< 15%) of BSA was released from the PEC beads except AC12. However, at pH 7.4, a large amount (> 80%) of BSA was released from AL in the first 3 h due to the rapid disintegration of the beads, whereas BSA release was retarded from complex beads due to the forming of PEC. The results suggested that the WSC/alginate beads could be a suitable polymeric carrier for site-specific protein drug delivery in the intestine. (c) 2006 Wiley Periodicals, Inc.