A number of authors have indicated that people who have greater and more satisfactory social activity tend to report that they have higher life satisfaction. This study was concerned with examining the relationship between involvement in activities and self-reported quality of life for people with severe and enduring mental illness. It is part of a larger study of quality of life for this client group. A random sample of 92 respondents was drawn from the population of people who met the criteria for severe and enduring mental illness in a Health Board in Northern Ireland. Data were gathered using a reliable and valid interview schedule based on a quality of life profile developed for the larger study. The findings indicated that over half of the respondents (56.5%, n=52) had no structured activity in their everyday life and there was a low level of participation in 14 listed activities of living. The respondents also reported a low level of self-reported quality of life. There was also a weak, but statistically significant, correlation between involvement in activities and self-reported quality of life. However, a moderate positive statistically significant correlation was found to exist between satisfaction with involvement in activities and self-reported quality of life. The implications for the care of people who are experiencing severe and enduring mental illness within and outside the United Kingdom are discussed.