We studied the safety of autologous peripheral blood stem-cell transplantation (PBSCT) in four patients with progressive multiple sclerosis. Clinical and magnetic resonance imaging outcomes were secondary end-points. Cladribine administration preceded filgrastim-primed PBSC collection, aiming for lymphocyte depletion. Conditioning was with antithymocyte globulin and cyclophosphamide. The procedure was well tolerated, but without obvious clinical benefit. The study was terminated when other therapeutic options with lower morbidity became available.