Glycerol was introduced as the cosolvent in the synthesis of zeolite A. The molar ratio of glycerol to Al2O3 in the synthesis solution, and the aging time were examined. The association of glycerol with water affected the nuclei formation during aging and resulted in different particle sizes. The sizes of zeolite A were controlled in the range of 0.4–1.5 μm when the glycerol to Al2O3 molar ratios were of 0–6. However, too much glycerol in the synthesis solution (molar ratio of glycerol/Al2O3 > 4) produced zeolite A with a small amount of sodalite. A long aging time (16 h) was necessary to make the product have a pure zeolite A structure and a small particle size.