INTRODUCTION AND AIMS: North America has witnessed a dramatic rise in fatal opioid overdoses due to the unwitting consumption of non-pharmaceutical fentanyl and its analogues. While some of the drivers of this crisis-including profitability and access to high-potency opioids through internet sources-also apply in Australia, to our knowledge, there have been no ongoing surveillance studies of local populations. Therefore, this pilot study aimed to detect unintentional fentanyl consumption among people who inject heroin through instant urine screening, and determine the feasibility and acceptability of voluntary urinalysis of clients at the Medically Supervised Injecting Centre, Kings Cross, Sydney. DESIGN AND METHODS: Brief surveys and urine drug screens were conducted with 67 participants in Wave 1 (October 2017) and 51 participants in Wave 2 (March 2018). Urine samples were tested with BTNX Rapid Response fentanyl urine strip test at a detection level of 20 ng/mL norfentanyl. These strips also cross-react to numerous fentanyl analogues. RESULTS: There were no cases where positive urine tests suggested unwitting fentanyl use detected in this study. DISCUSSION AND CONCLUSIONS: These negative findings contrast sharply with similar Canadian studies. While no cases of fentanyl-laced heroin use have been detected so far, we have demonstrated that this surveillance design is low-cost, feasible and scalable approach to monitoring the considerable public-health threat of undetected fentanyl and its analogues in Australia. Further validation of cross-reactivity of test strips would strengthen this method.