Chilean women have the highest smoking rates in Latin America. Prevalence in this population is about 40%. There are no national programs for smoking cessation at the primary care level. This study explores the feasibility and effectiveness of a brief counseling intervention targeted to women smokers of childbearing age who seek primary care in Santiago, Chile. A quasi-experimental design was used to compare the effect of an intervention based on the '5A' model developed by the National Cancer Institute in the United States and the standard care provided in two control clinics. Women smokers seeking care at the three primary care clinics were contacted during a 2 months period and offer to participate in the study. Sampling was stratified according to the age groups to ensure comparability between cohorts. Quotas were calculated for each age group. Participants were asked about their willingness to quit, self-efficacy, smoking behavior, addiction level as well as support received for smoking cessation. After 18 months of intervention all women were re-evaluated. A total of 773 women were recruited for the study; 76% of them completed the trial. Women smokers are characterized by a large percentage of light smokers with a low self-efficacy for quitting and with very low information on where and how to get assistance to quit. At study end, 15.2% of women reported quitting smoking at least for 1 month in the intervention clinic versus 7.8% in one of the control clinics (p < 0.05) and 14.6% in the second control clinic (p = NS). Over 70% of women in the intervention clinic were asked, assessed and received advice for quitting in comparison with <15% in the control clinics (p < 0.01). To conclude, a primary care intervention based on the '5A' model for smoking cessation is feasible and can have a significant effect in reducing smoking prevalence in this population.