Purpose: The purpose of this study was to evaluate the effects of a group art therapy on decreasing job stress and burnout of clinical oncology nurses. Methods: The study was conducted using a non-equivalent control group, non-synchronized design with repeated measures. A total of 29 clinical oncology nurses participated in the study; 15 were assigned in the experimental group, and 14 in the control group. Data were collected from May to July, 2014. The study questionnaires were administered in three different time points (pretest, 8th week, and 12th week). Data were analyzed using $x^2-test$, Fisher's exact test, t-test, paired t-test, and repeated measures ANOVA. Results: The first hypothesis "the experimental group with group art therapy will have lower job stress than that of the control group" was support (F=7.88, p=.003). The second hypothesis, "the experimental group will have lower burnout than that of the control group" was not statistically supported (F=1.80, p=.188). Conclusion: The findings of the study indicated that the group art therapy for oncology nurses may positively influence in decreasing job stress, which open a venue for developing a nursing intervention with group art therapy for clinical nurses in future.