Background: Data on the utilization and outcomes of urine drug tests (UDT) among advanced cancer patients is limited. The main objective of this study was to determine the factors associated with UDT ordering and results in advanced cancer outpatients. Methods: A retrospective chart review of 1058 patients seen from March 2014 to November 2015 at an outpatient supportive care clinic was conducted. Sixty-one patients on chronic opioid therapy who underwent UDT were identified. A control group of 120 patients who did not undergo UDT was selected for comparison of information on demographic and clinical characteristics. Results: 61/1058 patients (6%) underwent UDT. 33/61 patients (54%) had abnormal results. Multivariate analysis found that the odds ratio for UDT ordering was 3.9 in CAGE positive patients (p = 0.002), 4.41 in patients less than 45years (p < 0.001), 5.58 in patients with moderate to severe pain (ESAS pain score ≥ 4) (p < 0.001), 0.27 in patients with advanced cancer stage, (p = 0.008), and 0.25 in patients with moderate to severe fatigue (p = 0.001). Among 52 abnormal UDT results in 33 patients, the most common opioid findings were: prescribed opioids absent in urine (14/52, 27%) and un-prescribed opioids in urine (13/52, 25%). Conclusions: UDT was used infrequently among advanced cancer patients receiving outpatient chronic opioid therapy. Younger age, CAGE positivity, early cancer stage or NED status, higher pain intensity, and lower fatigue were significant predictors of UDT ordering. More than 50% of UDTs were abnormal. More research is necessary to better characterize aberrant opioid use in advanced cancer patients.