Psycho-educational interventions are not a substitute for analgesics, but they may serve as adjuvant therapy. Nurses can provide psychoeducational programmes to cancer patients to assist them in optimizing behavior that strengthen adjustment. The aim here was to determine the effects of psychoeducation on levels of adjustment to cancer in stage I-II breast cancer patients who met the study criteria (experimental group: 38 women, control group:38 women). The psychoeducational program consisted of eight 90 minute weekly sessions and data were collected using a questionnaire and the Mental Adjustment to Cancer Scale three times: before, six weeks and six months after the intervention. Data analysis was performed using descriptive statistical methods as well as the Chi square test, the Mann Whitney U test, repeated measures analysis of variance, the matched pairs t test and the Post Hoc Bonferroni test. The results at 6 weeks and 6 months after the program revealed that the experimental group had higher levels of "fighting spirit", lower levels of "helplessness/hopelessness, anxious preoccupation and fatalism" but there was no significant change in levels of "avoidance/denial" compared to the control group with regard to adjustment to cancer. In this study, psychoeducation was shown to cause positive changes in levels of adjustment to cancer in breast cancer patients