Importance: Urine drug test (UDT) can help screen and monitor aberrant controlled substance use among patients requiring opioid therapy for cancer pain. However, data on UDT utilization in patients with cancer pain remains limited. Objective: To determine the rate of UDT ordering and the factors associated with UDT order placement and the frequency and type of abnormal UDT findings. Methods: This retrospective study included adults (≥18 yrs) with a cancer diagnosis receiving prescription opioids for pain in an ambulatory pain clinic from November 2017 through April 2018. Descriptive statistics summarized patient characteristics and UDT findings. Logistic regression was used to identify factors associated with UDT ordering. Results: Five hundred fifty-eight patients were included in the study; the median age was 61 years, 52% were female, 74% were White, and 93% had active cancer. One hundred forty-one patients (25%) had UDT orders. On multivariate analysis, UDT ordering was associated with SOAPP-14 score ≥ 7 (OR, 2.03 95% CI 1.19–3.47 p = 0.009) and a history of substance use disorder (OR, 2.87 95% CI: 1.39–5.75 p = 0.004). Among those tested, 49 (35%) had abnormal results. A total of 80 abnormalities were identified, with some UDTs showing multiple findings; the most common was the absence of prescribed opioids (48%). Conclusions: Only one in four patients receiving opioids in an ambulatory cancer pain clinic received a UDT order, suggesting a more selective rather than routine use. UDT ordering was more common among patients with a SOAPP-14 score ≥ 7 and a history of substance use disorder. Among patients who underwent UDT, approximately one-third had abnormal results, with the absence of prescribed opioids or their expected metabolites being the most common finding. These findings suggest that UDT may provide important clinically relevant information as a component of comprehensive opioid monitoring. Further research is needed to establish evidence-based approaches to UDT implementation that promote consistent opioid safety practices.