Abstract: Dialectical Behavioral Therapy (DBT) has been found to be effective managing   anxiety symptoms and emotional regulation difficulties of drug addict patients.  Purpose: to evaluate the effect of a dialectical behavioral therapy on anxiety level and emotional regulation among drug addict patients. Design: A quasi-experimental research design two groups (study and control group pre/ posttest) was used to achieve the study purpose.  Setting:  the study was conducted at the drug addiction department of Meet-Khalaf Hospital, Menoufia Governorate, Egypt. Sample: A purposive sample of 80 drug addicted patients who attend inpatient in the psychiatric and Addiction Treatment Hospital in Meet-Khalaf, Shebin El-kom City, Menoufia Governorate, Egypt. Instruments: The data was collected using Structured interview questionnaire, Depression, Anxiety and Stress Scale-Anxiety (DASS-A -7), Emotion Regulation Scale. Results: there was a statistically significant reduction in anxiety symptoms in the study group after the therapy, 45% reporting no anxiety symptoms and 55% reporting mild anxiety level compared with before the therapy, 32.50% of the study group reported mild anxiety level and 62.5% experienced moderate anxiety level. There was a statistically significant improvement in the study group's emotional regulation levels after dialectical behavior therapy; 75% reporting   satisfactory emotional regulation as compared to before the therapy. There was a statistically significant negative correlation between total anxiety mean score and total emotional regulation mean score of the study group after dialectical behavioral therapy; where p value (p = 0.006). Conclusion: The dialectical behavioral therapy has a positive effect on reducing anxiety level and improving emotional regulation level among drug addict patients. Recommendation: Dialectical Behavior Therapy can be an effective treatment option for individuals struggling with drug addiction because it provides tools and strategies to help them manage the underlying emotions and behaviors that contribute to substance abuse.