Among injection drug users (IDUs) in Ottawa, the capital of Canada, prevalence rates of HIV (20.6 percent) and hepatitis C HCV (75.8 percent) are among the highest in Canada. Recent research evidence suggests the potential for HCV and HIV transmission through the multi-person use of crack-smoking implements. On the basis of this scientific evidence, in April 2005, Ottawa's needle exchange programme (NEP) commenced distributing glass stems, rubber mouthpieces, brass screens, chopsticks, lip balm and chewing gum to reduce the harms associated with smoking crack. This study aims to evaluate the impact of this initiative on a variety of HCV- and HIV-related risk practices. Active, street-recruited IDUs who also smoked crack consented to personal interviews and provided saliva samples for HCV and HIV testing at four time points: 6-months pre-implementation (N=112), 1-month (N=114), 6-months (N=157) and 12-months (N=167) post-implementation. Descriptive and univariate analyses were completed. Following implementation of the initiative, a significant decrease in injecting was observed. Pre-implementation, 96 percent of IDUs reported injecting in the month prior to the interview compared with 84 percent in the 1-month, and 78 percent in the 6- and 12-month post-implementation interviews (p<.01). Conversely, approximately one-quarter of participants at both the 6- and 12-month post-implementation evaluation points reported that they were smoking crack more frequently since the availability of clean equipment--25 and 29 percent, respectively. In addition to a shift to a less harmful method of drug ingestion, HCV- and HIV-related risks associated with this method were reduced. Among crack-smoking IDUs sharing pipes, the proportion sharing "every time" declined from 37 percent in the 6-month pre-implementation stage, to 31 percent in the 1-month, 12 percent in the 6-month and 13 percent in the 12-month post-implementation stages (p<.01). Since distributing safer crack-smoking materials by a NEP contributes to transition to safer methods of drug ingestion and significantly reduces disease-related risk practices, other NEPs should adopt this practice.