This paper describes the management techniques developed over 20 years of experience with free-ranging groups of callitrichids at Durrell Wildlife Park (formerly Jersey Zoo), UK, with an additional 12 years of information from Zürich Zoo, Switzerland. Seventeen groups of eight different species have been released in woodland areas at Durrell, and two groups at Zürich. Release periods ranged from 2 weeks to 14 years. The evolution of release protocols is described, along with brief descriptions of problems that have occurred. The advantages and problems of maintaining callitrichids in free-ranging environments are discussed.