Chronic smoking is a disease associated with long-time daily consumption of tobacco products and is synonymous with nicotine dependence. Nicotine is the major determinant of tobacco addiction, causing psychoactive pharmacological effects, which together with the genetic, social and environmental factors, learned or conditioned, are the substrate of smoking status. We conducted a retrospective study on a cohort of 535 smokers presenting to the Smoking Cessation Counseling Medical Office of the Iasi Clinical Rehabilitation Hospital between January 2009-December 2012 aimed at studying the psychosocial and medical parameters associated with the vulnerability to nicotine addiction. The analyzed psychosocial factors were age, sex, marital status, absence or presence of other smokers in home and motivation to quit smoking. The measurable parameters of tobacco dependence were the number of previous attempts to quit smoking, the amount of cigarettes smoked (pack years), the carbon monoxide breath test, and score of Fagerström test for nicotine dependence. The results showed that the profile of the smokers with nicotine addiction who attempts to quit smoking is middle-aged men, married, with smoking partner, and severe chronic smoking expressed in a large number of pack years and elevated breath CO levels, and concern with his own health status. The severity of nicotine dependence is best reflected by the objective medical parameters, but its psychological components are still undervalued in practice, the professionals involved in the fight against tobacco addiction being deprived of major levers for action.