At request of the Minister of Social Affairs and Employment, the Health Council of the Netherlands evaluates and judges the carcinogenic properties of substances to which workers are occupationally exposed. The evaluation is performed by the subcommittee on Classifying Carcinogenic Substances of the Dutch Expert Committee on Occupational Standards of the Health Council, hereafter called the committee. In this report, the committee evaluated cyclosporin. Cyclosporin is an immunosuppressive agent that is given to patients to prevent graft-versus-host reactions after organ transplantation, and to control certain diseases in which the immunological defense plays a role.