To prepare microcapsules composed of chitosan (CS), a templating method is developed using poly(styrene sulfonate) (PSS)-doped porous calcium carbonate (CaCO3) templates as sacrificial templates. First, CS is absorbed onto PSS-doped porous CaCO3 templates, and then the absorbed CS is covalently cross-linked with each other by using glutaraldehyde. Porous CaCO3 templates are dissolved with disodium ethylenediaminetetraacetate dihydrate and the resultant CS capsules ranged from 2 to 5 mu m in diameter. Nitrogen adsorption-desorption analysis are applied to characterize the porous CaCO3 templates, the BET surface area and total pore volume are 220 m(2)/g and 0.36 cm(3)/g, respectively. Field-emission scanning electron microscopy and transmission electron microscopy were used to characterize the CS capsules morphology. Confocal laser scanning microscopy images reveal that the capsules have been labeled with green fluorescein isothiocyanate. The gradual deformation of capsule in response to bulk osmotic pressure created by CS solutions has also been discussed.