Context: This article presents specific approach for microencapsulation of Lactobacillus casei using emulsion method followed by additional coating with whey protein. Methods: Experimental design was employed using polynomial regression model at 2nd level with three independent variables, concentrations of alginate, whey protein and CaCl2. Physicochemical, biopharmaceutical and biological properties were investigated. Results: In 11 series generated, negatively charged microparticles were obtained, with size 6.99-9.88 mu m, Ca-content 0.29-0.47mg per 10mg microparticles, and viability of the probiotic 9.30-10.87 log(10)CFU/g. The viability after 24 hours in simulated gastrointestinal conditions was between 3.60 and 8.32 log(10)CFU/g. Discussion: Optimal formulation of the microparticles that ensures survival of the probiotic and achieves controlled delivery was determined: 2.5% (w/w) alginate, 3% (w/w) CaCl2 and 3% (w/w) whey protein. Conclusion: The advantageous properties of the L. casei-loaded microparticles make them suitable for incorporation in functional food and/or pharmaceutical products.