The aim of this study was to gather data on the safety of the HPV-16/18 AS04-adjuvated vaccine among women aged 25, evaluating the frequency and severity of adverse events reported after vaccination and to compare the results obtained with previously published data regarding a sample of Italian preadolescents. Every woman residing in the province of Florence and in the age group targeted by the cervical cancer screening was invited to participate. Participants registered daily, for 14 d post-vaccination, solicited local and systemic reactions, as well as unsolicited adverse events in a developed ad hoc safety diary card. Data were collected in a database in Access and analyzed using STATA 11 SE statistical software. A total of 271 participants were recruited in the study group. All three diary cards were completed and delivered by 186 subjects (85.7% of participants). In all, a total of 616 diary cards were collected: 216 after the 1st dose, 209 after the 2nd dose and 191 after the 3rd dose. No severe symptoms were registered. The most frequently reported adverse reaction proved to be pain at the site of injection (83.4% of doses), followed by local swelling (20.8%) and pyrexia (14.6%). The safety and tolerability of the HPV-16/18 AS04-adjuvated vaccine in this sample of adult women aged 25 did not differ much from that previously observed in a sample of preadolescents Italian girls. Fever and local pain were however more frequently registered in our sample of adult women.