Medical rehabilitation arranged by the Social Insurance Institution of Finland is provided for children with severe disabilities. The study aimed to find out which service characteristics were associated with perceived outcomes of rehabilitation. Parents whose children had participated in rehabilitation (n = 496) responded to a mail questionnaire that included questions on service characteristics and possible outcomes. Based on factor analysis, four outcome variables were formed. Logistic regression analysis was used to identify the particular service characteristics that were associated with the perceived outcomes. The family’s participation in rehabilitation planning and the child’s willingness to participate in rehabilitation activities were associated with good outcomes. Having a contact person for the rehabilitation process predicted child and family empowerment outcomes. The results emphasize the significance of establishing a good partnership between the professionals and the family; of developing the contents of the rehabilitation program, so that they motivate the child, and of organizing service coordinators for each family.