Calcium molybdate nanoparticles were synthesized using a liposome based on egg phosphatidylcholine and cholesterol. The molybdate ion was encapsulated into the liposome, and then a calcium chloride solution was added to the liposome suspension. The molybdenum release kinetics from the liposome to the bulk solution was determined to be 8 ppb h(-1). The calcium ion caused aggregation of the liposomes at a higher concentration (>2.5 mM). By using a 1mM calcium solution, the nanosized calcium molybdate (similar to 20 nm) precipitated on the liposome surfaces.