Background: Stress can refered as an adaptation process to a new environment. The most effective way to reduce negative effect that caused by stress on first year students is Cognitive-behavioral stress management. Objective: The objective of this research is to study whether the effectiveness of Cognitive-behavioral method as stress management in decreasing stress among the first year students at School of Dentistry UMY. Methods: The type of the research was quasi-experimental with pretest-intervention-posttest design. The sample consisted of 40 first year students at School of Dentistry UMY chosen through purposive sampling. The analysis was done using Wilcoxon test since the data distribution was not normal. Results: The research indicated that there was significant difference before and after being treated with the stress management with its probability value of 0,000 (p<0,05). The average result indicated a decreasing value of 9,60. Conclusion: Cognitive-behavior method is effective as stress management in decreasing the level of stress among first year students of School of Dentistry UMY.