The centrifugal sifter for screening small batches of pharmaceutical powders and other contamination-sensitive products, can be disassembled rapidly, and sanitized manually or in an autoclave. As material is gravity-fed into the unit, rotating helical paddles accelerate particles, continuously propelling them against the cylindrical screen and through screen apertures. On-size material discharges through the first of two outlets, into a storage vessel or processing equipment. The paddle assembly, which does not contact the screen, also serves to break-up agglomerated materials. Oversized particles unable to pass through the apertures, exit through the end of the screen cylinder and fall through a second outlet for discarding or re-processing. Cylindrical screens are offered in woven nylon, monofilament, wire mesh stainless steel, perforated plate and stainless steel wedge wire, to accommodate a wide range of pharmaceutical products. The unit is constructed of stainless steel with continuous welds ground and polished to FDA as well as 3A, BISSC and other sanitary standards.