Approximately 60%-80% of all multiple sclerosis (MS) patients are heat sensitive. The aim of this study was to gain information on the effects of an assistive device, the cooling-suit, on MS-patients' self-care ability and also practical implications. A single-case approach was adopted in a quasi- experimental before-and-after study. The cooling-suit was used in their own homes by 10 individuals with diagnosed MS in different stages from relapsing-remitting to chronic progressive. Data collection procedures were self-assessment through a structured assessment-instrument, an open-ended interview before and after the intervention and a diary written during one week. The selected instrument, the MS Self-Care ADL Scale, has been developed for persons with MS and was translated into Swedish. The results showed increased self-care ability during and after use of the cooling-suit. However, different aspects of daily life activities were improved and to a varying extent. It is concluded that the study participants were supported and empowered in different activities of daily life such as walking and transfer and reduced voiding problems by using the cooling-suit. Some difficulties in handling the cooling-suit were also reported.