Encouraging patient participation in medical and nursing care is an active expression of respect for a person's autonomous choice. The aim of the present study was to compare preferences about the degree of participation in treatment decision-making in a group of patients with colo-rectal cancer before and one-year after surgery, and further to compare these preferences to the patients’ actual participating role before surgery and their sense of coherence. Fifty-five persons diagnosed as having rectal or colon cancer were studied. The following instruments were used: The Control Preferences Scale (CPS) and the Sense of Coherence Scale (SOC). Results show that 71% and 75%, respectively, chose a collaborative participation role, before surgery and at follow-up. A majority, 64%, maintained their preferred role from before surgery to the one-year follow-up. Agreement between the preferred and the actual participating role was achieved by 31%. There were no statistically significant differences between the preferred role and with respect to the participants’ sense of coherence either before surgery or at follow-up. The sense of coherence seemed not to be related to the preferences before surgery or at follow-up preferences. Further research is needed to elaborate the understanding about patients’ preferences for participating in treatment and care decisions.