Multiple sclerosis (MS) is a disorder of the central nervous system that occurs in 55,000 - 75,000 Canadians. MS causes symptoms such as muscle weakness, poor balance, pain, fatigue, bladder and bowel dysfunction, and sexual dysfunction. Although high rates of sexual dysfunction are well documented among MS patients, predictors of sexual satisfaction among this population have been understudied. Illness intrusiveness (how intrusive one finds his or her illness) has been found to mediate the link between illness symptoms and quality of life. Therefore, the mediational role of illness intrusiveness between sexual dysfunction and sexual satisfaction was examined in this cross-sectional study.Eighty-two women with MS completed self-report measures to investigate how illness intrusiveness mediated, and age moderated the relationship between sexual dysfunction and sexual satisfaction. Higher illness intrusiveness into intimacy mediated sexual dysfunction and sexual satisfaction. The impact of illness intrusiveness and other relationship variables on sexual satisfaction are discussed.