The preparation of 3D scaffolds using poly(3-hydroxybutyrate) (PHB) and chitosan (CTS) has been proposed because of the favorable interactions of these materials with mammalian cells in particular osteoblasts (HOB). In this work, a new method of producing porous 3D scaffolds based on the swelling of a dense matrix of PHB and CTS was developed. Scanning electron microscopy images showed the formation of an interconnected porous CTS structure inside a PHB structure. The pore formation was attributed to the swelling of CTS. The scaffolds presented 70% porosity, heterogeneous pore-size distribution, and a compressive modulus equal to (13.07 +/- 0.014) MPa, which is close to that of cancellous bone. In vitro cytotoxicity assays indicate that the scaffold was not cytotoxic. Its morphology, chemical, and physical properties indicate that the scaffold produced by this new methodology has potential applications in bone-tissue engineering, with drug-delivery capabilities. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013