Immobilized Nicotiona tabacum cells in calcium alginate gel beads were prepared under various conditions and then were cultivated. The effects of different conditions of preparation, in relation to concentration of calcium ions (Ca2+), on intraparticle cell growth and cell leakage from beads were investigated experimentally. As the amount of Ca2+ incorporated into the beads increased, the numbers of cells leaked fi om the beads into the medium decreased. However, cell growth was inhibited by high Ca2+ concentrations in the beads. Optimal conditions existed, which prevented cell leakage without inhibiting intraparticle cell growth. The effect of adding CaCl2 to the culture medium was also studied. The Ca2+, used for the alginate crosslinking, gradually leached from the beads with increasing cultivation time, such that the beads gradually became brittle and fragile. The addition of CaCl2 was effective in preventing Ca2+ loss from the beads and cell leakage.