New 252Cf encapsulation techniques have been developed which offer possibilities of variation in source strength and geometry. These techniques involve the concentration of 252Cf by extraction into an organic phase, followed by calcination to the oxide, and either fusion into a silica sphere or compression into an aluminum container. To date, sources containing from 8 to 100 µg of 252Cf have been prepared by fusion of the oxide into silica spheres about 1.6 mm in diameter. Sources containing up to 5 mg of 252Cf have been prepared by compression of mixed californium and aluminum oxides in aluminum powder to form aluminum cylinders 9.5 mm high and 6.5 mm in diameter. These new techniques make a significant contribution toward the technology necessary for the fabrication of 252Cf neutron sources, which are finding useful applications in many fields, including cancer therapy, mineral exploration, oil-well logging, on-site production of short-lived isotopes, and on-line analysis of flowing process streams.