This study deals with the association between life events, family history of mammary carcinoma and breast cancer. It was guided by a model consisting of events, family disposition and age at the side of the independent variables. In addition to these factors 'lack of social support' was introduced. The latter is conceptualized as a vulnerability factor capable of aggravating the impact of events without having an independent effect. There was no hypothesis on chronic difficulties, so this is exploratory. This research was conducted as a so-called 'limited prospective' design. Women with a suspicious breast lump were interviewed before surgery. After having confirmed the outcome of the surgery the sample was divided into a group with cancer and cases with a benign diagnosis. Women with gall stones were introduced as another control group. The interviews were performed along a semi-structured schedule, tape recorded and analyzed by using Brown and Harris' Life Events and Difficulties Scale. The analyses were made with 33 women with cancer, 59 with a benign tumor and 20 with gall stones. In the 'malignant' group the severest events was four times as high as in controls. All other degrees of threat were equally distributed over the groups. Chronic difficulties of the highest degree of severity also occur more often in the cancer group. They are not independent from events so that analyzing them separately is not useful. The rate of family history of breast cancer does not differ between the tumor groups, but is much lower in the gall stone patients. In the cancer group there is an association between this possibly hereditary factor and severe events, in the 'benign' group both are uncorrelated. The life event effect is explained in context of a higher illness susceptibility due to a hereditary disposition. For events occurring without it an explanation remains unclear.