Multiple sclerosis (MS) patients are often unable to adequately fulfill their established roles due to physical disabilities and cognitive changes, making this chronic illness particularly threatening to personal identity. Twenty-five MS patients and 25 healthy controls were asked to recall five self-defining memories (SDM). Overall characteristics of SDM did not differ between patients and controls; MS patients displayed preserved capacity to draw meaning upon past events. Moreover, almost two-thirds of MS patients mentioned at least one illness related SDM and about 25% of patients' SDM referred to MS. These memories were experienced as more negative and associated with more tension than other SDM but led toward more positive emotion and less negative emotion over time; they were also more central and more integrated to the personal identity. We concluded that self-challenging events due to MS may trigger both cognitive and emotional processes enabling the integration of illness in patients' self-representations.