Background : Smoking causes an imbalance in the autonomic nervous system. In general, nicotine causes increase in the activity of the sympathetic nervous system, causing the release of neurotransmitters, and resulting an increase in blood pressure (BP). Continuous increase in BP will cause activity that is dominant in the sympathetic nervous system compared to the parasympathetic nervous system. Sympathetic nervous system activity can be measured using the cold pressor test (CPT) method by looking at the blood pressure response to cold stimulus as an indicator of sympathetic nerve activation. Research Purpose : The purpose of this study was to determine the differences of autonomic nervous system in adolescent smokers and nonsmokers. Research Methods : This type of research is descriptive comparative. The sampling technique uses combination of purposive and accidental sampling. The subjects of this study were 48 adolescent smokers and nonsmokers in Kasihan, Bantul, Yogyakarta. The analysis techniques used are univariate and bivariate. Results : The results showed that respondents were dominated by male respondents aged 18-22 years, the results of this study showed there were differences of autonomic nervous system in adolescent smokers and nonsmokers, which in smokers diastolic BP.