Abstract Background National drug-involved overdose deaths continue to rise with deaths involving synthetic opioids (primarily fentanyl) showing the most significant upward trend. Fentanyl is a synthetic opioid with short-acting analgesic activity and a 50–100 times higher potency compared to morphine. Pharmaceutical fentanyl is typically used to treat patients with severe or chronic pain. In contrast, “illegal” fentanyl has frequently been added to other drugs including heroin, cocaine, methamphetamine, and MDMA to increase their potency and contributing to overdose deaths. In this study, we have investigated trends in fentanyl and fentanyl analogs positivity at a large academic medical center. Methods Retrospective analysis of results reported over seven years (2015–2021) for untargeted urine drug screens included testing performed for acute exposure and compliance. Presence of fentanyl, fentanyl analogs, and other prescribed or illicit used drugs was determined by gas chromatography—mass spectrometry (GCMS). Overall positivity was calculated as a percentage of total reported results. Results Fentanyl, and fentanyl analog positivity was determined for 40 782 urine drug screen results. Overall positivity for fentanyl and fentanyl analogs increased 3.8-fold over the past seven year from 1.53% (2015) to 5.78% (2021). Co-positivity with other illicit drugs such as cocaine and heroin also increased from 7% and 8% respectively, in 2015, to 42% and 13%, in 2021. Presence of fentanyl analogs such as fluorofentanyl, despropionylfentanyl, and acetylfentayl increased in the recent years as well. Conclusion Our data reveals increased positivity of fentanyl and fentanyl analogs present with cocaine, heroin, or their metabolites suggesting increased use of illicit fentanyl. The high prevalence supports the inclusion of fentanyl on routine urine drug screen immunoassays, or at a minimum as a reflex with a positive opiate screen.