The distinction between affect and cognition has been put forward to clarify the lack of differences found in studies describing quality of life under deteriorated circumstances, such as serious illness. In the study reported here, cancer patients under treatment (n = 201) were compared with a random sample from the normal population (n = 200). As hypothesized, the affective component of life quality turned out to be more severely impaired than the cognitive component. Besides, it was investigated which factors contribute to the affective and the cognitive component of the quality of life of cancer patients under treatment. In cancer patients affect proved more strongly related to the physical domain. Cognition on the other hand was more strongly related to coping resources, especially personality characteristics like the level of self-esteem. It is concluded that an affective measure of quality of life is more sensitive to change in patients. The stability of life quality is attributed to the rather strong relation the affective and the cognitive component both have to coping resources.