The NIIDRBS captured information on drug- and sex-related risk-behaviours during the last six months in the community prior to the current incarceration, and during the past six months in prison prior to completion of the questionnaire. [...] In fact, among inmates who injected in both the community and prison, 33% used a needle previously used by someone else during the past six months in prison but not during the last six months in the community. [...] In regards to unprotected sex, the bulk of men and women who reported unprotected sex with a regular partner in prison had actually engaged in the behaviour in the community (5% and 14%, respectively). [...] The NIIDRBS captured information on drug-related and sexual behaviours during the last six months in the community prior to the current incarceration and during the last six months in prison prior to completion of the questionnaire. [...] In regards to risk-behaviours associated with the spread of blood-borne and sexually transmitted infections, inmates reported on their risk- behaviours during the last six months in the community prior to their current incarceration and during the past six months in prison prior to survey completion.