A new microencapsulation technology of polyelectrolyte complex beads which produce very small particles (1-50 mu m) with particle size control has been developed. The polymers used were sodium alginate as polyanion and barium chloride as polycation. To do that, an air-blast atomizer that uses compressed air was used. This works by spraying a solution of sodium alginate in a solution of barium chloride, which induces the gelation. The air flow rate, alginate flow rate and viscosity of the alginate solution effects were studied. The behaviour curves of the system were built with the microparticles size data obtained at different operation conditions. These curves will allow knowing the operation conditions for a suitable rnicroparticle size. (c) 2006 Elsevier B.V. All rights reserved.