<p><strong>Objective: </strong> To examine the rates and patterns of tobacco and e-cigarette use amongst two samples of illicit drug users in Australia.</p> <p><strong>Method: </strong> Data were obtained from the 2015 Illicit Drug Reporting System (IDRS) and the 2015 Ecstasy and Related Drugs Reporting System (EDRS). These studies comprised cross-sectional samples of 888 people who inject drugs (PWID) and 763 regular psychostimulant users (RPU).</p> <p><strong>Results: </strong> Tobacco was consumed by the majority of both samples, however, use in the 6 months preceding interview was significantly higher amongst PWID (92.2%) than RPU (82.4% [OR 2.53 95% CI 1.86-3.44]). Inversely, PWID were less likely to have a history of e-cigarette use: 31.5% of PWID reported lifetime use of e-cigarettes (vs. 57.0% of RPU [OR 0.35 95% CI 0.28-0.42]) and 18.1% reported use in the 6 months preceding interview (vs. 33.7% of RPU [OR 0.44 95% CI 0.35-0.55]). PWID were more than three times as likely than RPU to report using e-cigarettes as a smoking cessation tool (OR 3.09 95% CI 2.03-4.71), but were less likely to use e-liquids that contained nicotine (OR 0.52 95% CI 0.32-0.83). Higher levels of poly drug use, daily tobacco use, recent use of synthetic cannabinoids and employment status were found to be significantly associated with e-cigarette use.</p> <p><strong>Conclusion:</strong> The use of e-cigarettes was relatively common amongst Australian samples of PWID and RPU. Whilst the majority of PWID reported using e-cigarettes as a smoking cessation tool, it appears that RPU are using them for experimental or recreational purposes.</p>