The aims of this study were, first, to describe and compare the perceived well-being and general health, symptoms and coping ability of a group of patients with colo-rectal and gastric cancer before and after surgery; secondly, to describe the patients' perceptions of the hospital stay and their difficulties after discharge from the hospital; and thirdly, to investigate a possible relationship between sense of coherence and well-being. Seventy-nine (36 men, 43 women) consecutively selected patients diagnosed with colo-rectal or gastric cancer participated in the study. The Health Index (HI), the symptom checklist, the Sense of Coherence Scale (SOC scale), a study-specific questionnaire and a single item were used. Six weeks after surgery many of the cancer patients perceived that their well-being was poorer on the HI subscales energy, sleep and mobility than before. Bowel function had improved, and pain, which was a common symptom before surgery, was perceived as having lessened after surgery. Furthermore, the sense of coherence was shown to be related to the cancer patients' well-being as measured by the HI. Patients living with relatives rated their well-being as better than that of patients living alone. The problem areas identified after discharge concerned mobility, bowel function, fatigue, pain, nutrition, worry, difficulties in sleeping and problems with the wound. The instruments used in the study are seen as screening instruments to further structure the nursing-care plan, so that the patients' perceptions of the disease situation can also be taken into consideration.