Smoking has become a main risk factor for morbidity and mortality. Nicotine is the main toxic agent of the cigarette and is responsible for the addiction; it also plays an important role on the inadequate neurovegetative balance changing the autonomic modulation of the heart rate variability (HRV). Regular exercise is an important tool for improving the HRV and decreasing the dependence to nicotine. PURPOSE: To establish the effect of a supervised aerobic program on the autonomic modulation of HRV in habitual cigarette smokers (HCS) females and to assess the changes on nicotine dependence, motivation for smoking cessation and the number of cigarettes smoked during the day. METHODS: Through a case control study, six young HCS women were the case group (CAG) and participated on an aerobic exercise program during 8 weeks. The training consisted of a session of 35-40 minutes, 3 days a week, with a Borg scale intensity of 13-14 and an average caloric expenditure of 242,2 per session. The HRV was measure following different positions during 20 minutes: supine horizontal position, breathing cycle of 10 or 12 repetitions for a minute, standing position, 30 squats for 45 seconds and recovery. This protocol was performed at the beginning and at the end of the study. The test was always made after a non smoking period of 8 hours. Nicotine dependence was established using the Fagerstrom test, motivation for smoking cessation was assessed using Richmond test. The 6 women on the control group (COG) followed the same test but did not take part on the training sessions. RESULTS: At the end of the exercise program, the number of cigarettes smoked by day on CAG was lower compared to COG (4,0 vs. 0, 6; p<0,05). Nicotine dependence was lower on CAG compared to COG (1,16 Vs. 0,16; p<0,05) as well as the motivation for smoking cessation (p=0,097).; HRV between CAG and COG has no statistical difference; although individual differences were seen in CAG between women who quit smoking and active smokers specifically in mean heart rate, HF power (ms2/Hz) during horizontal position, mean RR (ms) and pNN50 (%) both on recovery. CONCLUSION: An aerobic exercise program seems to decrease the nicotine dependence and the number of cigarettes smoked by day on a group of HCS females; it also improved the motivation for smoking cessation. HRV between CAG and COG was not different.