Hurler syndrome (HS) is a severe inborn error of metabolism causing progressive multi-system morbidity and death in early childhood. At present, stem cell transplantation (SCT) is the only available treatment that can prevent central nervous system disease progression in HS patients. Although SCT has been shown to be effective for several important clinical outcome parameters, the reported clinical outcome after successful SCT is variable among HS patients and there are still some major limitations. This review will focus on the clinical outcome of HS patients after successful SCT, with particular emphasis on the long-term outcome and complications. In addition, factors that are suggested to contribute to the variable outcome are outlined, as well as the limitations of SCT in HS patients.