The purpose of this report is to provide a summary of the substances that were submitted to drug checking in sites across British Columbia, as well as highlight any trends in the unregulated drug supply in 2021. The data is presented both by health authority regions, and by drug category, to provide an in-depth look at how the unregulated drug supply varies between region, and how it changed across the year. The data presented was collected by technicians at community sites where drug checking is available, using benzodiazepine and fentanyl immunoassay test strips and Fourier-transform infrared (FTIR) spectroscopy. Samples were grouped into the following categories: opioids, stimulants, depressants, psychedelics, other, polysubstance, and unknown.