The objective of this survey is to evaluate knowledge and sexual behaviour among young Italians (19 to 24 years). The project, began in 1993, is being carried out through an anonymous postal questionnaire, sent to a representative sample of the young Italian population (a total of 52,000 people from 363 Italian towns). In the present intermediate evaluation, we have analysed 6929 of the 18,132 questionnaires sent till now, with all Italian regions being proportionally included. Our data show that, after sexual activity has been started, it hardly seems to be limited to monogamy or to be always regulated by AIDS-preventing practices. Data show that the age of the first sexual intercourse is increasing (after age 18) and that condoms are used more frequently, particularly in occasional sex.