Purpose: The purpose of this study was to determine the effectiveness of group trainnig based on improving quality of life on hope and happiness of cancer patients. Method: This was a semi-experimental, pre-test, post-test control group desing with follow-up of 3 months. The statistical population of the study consisted of all individuals with cancer diagnosis who referred to Omid Hospital in Mashhad in 2015. 30 individuals were selected by purposeful sampling and interviewed. After initial screening in terms of Hope and happiness variables, they were randomly assigned to two groups of 15 individual (experimental and control). Patients in the experimental group received training on quality of life-based treatment techniques in group format for 2 times a week in 10 session of 90 minutes, while the control group did not receive any interventions. Oxford Happiness and Schneider Hope questionnaire were used to collect data. Results: The results of one-way covariance analysis and paired t-test on pretest, test and follow-up scores showed that after modifying the pre-test scores between two groups, there were significant differnces in hopefulness (P <0.05) and happiness P <0.01). Conclusion: According to the findings of this study, it is suggested that in counseling and therapeutic clinics, the quality of life based therapy should be used to increase the hope and happiness of cancer patients.
