Most studies investigating the reasons for smoking initiation are based on adolescents or young individuals. We considered the issue in a large dataset on the general Italian population. Six population-based surveys on smoking were conducted annually from 2005 to 2010 on representative samples of Italian individuals aged 15 years or over, involving more than 3000 individuals each year. A specific question on the main reason to start smoking was asked to 7469 ever smokers. Overall, 59.9% of ever smokers started smoking before 18 years of age and 33.6% started smoking before 16 years of age. Among ever smokers, 61.1% reported having started smoking because of the influence of friends, 15.6% for enjoyment and satisfaction, 9.0% to feel mature and independent, 6.6% because of the influence of partner/family, 2.5% because of stress, 1.9% to feel more secure and 1.8% for curiosity. The finding that the majority of Italian men and women - particularly those who started smoking at a young age - started smoking because of the influence of friends suggests that antismoking campaigns should consider social influence, resistance and the dimension of self-esteem. An improvement in the legislation prohibiting the purchase of tobacco products by minors aged less than 18 years and a smoking ban in school courtyards are urgently required in Italy.