Objectives: Dipping tobacco is highly prevalent worldwide and in Sudan among adult males and is associated with cardiovascular hazards. The main objective of this study was to determine the effects of ‘tombak’ (local name for dipping tobacco in Sudan) dipping on heart rate variability and autonomic functions among adult males. Methods: Blood pressure and heart rate variability were recorded in 60 male tombak users (study group) at least 5 hours before using the tombak and after 30 minutes of use. Forty male non- users of tombak or any other tobacco products were included as a control group. Results: Measurements 5 hours before tombak dipping revealed statistically significant decrease in high frequency power in tombak users. Acute responses to tombak dipping included statistically significant increase in diastolic blood pressure, increase mean arterial pressure, decrease mean NN and decreased square root of the mean squared differences of successive NN intervals. Conclusions: the study results indicated disturbances in the sympatho-vagal balance with domination of sympathetic effects in the regulation of the cardiac activity and peripheral resistance in tombak users.