We have prepared targets of many of the actinide elements, e.g., U, Pu, Am, Cm, Bk, Cf, Es, and Fm, for use in a comprehensive series of fission cross-section measurements. Other experiments requiring actinide targets have involved accelerator bombardments, e.g., irradiation of 253Es and 257Fm at the HILAC, and symmetry studies of neutron-induced fission, e.g., recent studies of 257Fm and 258Fm fission. The experimental techniques require the targets be uniformly deposited in a thin layer on various backing materials such as Al, Ni, Pt, Be, Cu, and stainless steel. The backing materials ranged in thickness from 0.007 cm to 150 cm with target diameters ranging from 2 to 250 mm. In most cases the rarity of the nuclide required a deposition method that produces high yields, ≥90%. The various methods developed to produce acceptable targets may be summarized as follows: Electrodeposition technique (1) Dilute nitric acid electrolyte: Useful for actinides on a tracer level where high yields and small target area are desirable (e.g., einsteinium, fermium targets on a beryllium backing plate). (2) Isopropyl alcohol-dilute nitric acid electrolyte: Useful for actinides from tracer to microgram levels where uniformity of deposit is critical (e.g., berkelium, curium, einsteinium targets for Physics VIII cross-section experiment). (3) Ammonium chloride electrolyte: Useful for deposition of massive amounts (<1 mg/cm 2) of actinides over large areas (180 cm 2). Also useful for deposition of actinides that are subject to hydrolysis in dilute acid (e.g., preparation of 232U, 238Pu, 242mAm targets on nickel foils for fission cross-section measurement). Chemical replacement technique. (1) The method is useful for plating uranium on aluminium. The preparation of 1-mg/cm 2 deposits on 1-mil aluminum is typical. Following deposition, it is usually necessary to determine the absolute amount of the actinide in the targets. This quantity is most often determined by absolute alpha counting. In the case of targets with high activity levels (10 6–10 11 αdis/min) and large backing plates (8-in. diam.), a new low-geometry counter has been designed, built, and calibrated for this purpose. Uniformity of sample deposition has been monitored through alpha counter scanning techniques.