Depending on the degree of protection and security experienced in their early childhood, individuals develop a secure versus insecure attachment style. This specific attachment style intervenes in adulthood, in the form of internal working model, under condition of stress, guiding perceptions, causal attributions and communication, especially in close relationships. The Attachment Style Questionnaire is a paper and pencil self-administered questionnaire to assess attachment styles in adults (ASQ, Feeney, Noller e Hanrahan, 1994). The aim of the present study is to contribute to the validation of the ASQ in an Italian sample: 402 University students participated to the study. Cronbach’s alpha coefficients, ranging from .64 to .71, and correlations between ASQ subscales and the descriptions proposed by Hazan e Shaver (1987) confirm psychometrics and global validity of this instrument. Through confirmatory factor analysis, a three factor model (Secure, Avoidant and Anxious) has been contrasted to a two factor model (Secure versus Insecure), with the former fitting data more appropriately than the latter model. Overall, results replicate those previously obtained in a somehow different Italian context: the ASQ is thus proposed as a reliable, easy to administer, and cheap self-administrable questionnaire to assess individual differences concerning attachment styles in adults. In the general discussion some methodological topics, related to the assessment of adult attachment, are approached.