Background: One of the methodological barriers to conducting research on interventions for NOMU (Aberrant Opioid Use Behaviors) among cancer patients is the lack of data on the frequency of this problem. Although the frequency of risk factors has been established by our group and others, not all the patients with risk factors will be diagnosed with having NMOU behaviors, and some patients with no previous risk factors will engage in NMOU. AIM: To characterize the overall frequency of NMOU for a duration of 3 months, as well independent predictors for NMOU. Methods: In this retrospective study, 1558 consecutive patients referred to supportive care clinic (SCC) from 3/18/2016 to 6/6/2018 were reviewed for development of NMOU using established diagnostic criteria. Patients were eligible if they were ≥18 years, had a diagnosis of cancer, and were on opioids for pain for at least a week. All patients were assessed with the Edmonton Symptom Assessment Scale (ESAS), SOAPP-14, and CAGE-AID. Descriptive statistics, spearman correlation coefficient, multivariate analysis were performed. Results: 299 patients (19%) had ≥1 NMOU behavior. The median (IQR) NMOU behavior was 1 (1-2); range 1-10. Most NMOU occurred at 1^st and 2^nd follow up visits. The most frequent NMOU behavior was unscheduled clinic visit for inappropriate refills. 29/299 (10%) NMOU patients received specialized care for high-risk for aberrant opioid misuse by interdisciplinary team. Results of multivariate logistic regression model showed Marital status (Divorced vs. Married, OR=1.47, 95% CI: 0.98, 2.22, p=0.654 (marginally significant); Single vs. Married, OR=1.68, 95% CI: 1.15, 2.46, p=0.0079), SOAPP (Positive vs. Negative, OR=1.42, 95% CI: 1.05, 1.93, p=0.0238), morphine equivalent daily dose (MEDD) (OR=1.004, 95% CI: (1.003, 1.006), p<0.0001) and ESAS pain (OR=1.11, 95% CI: 1.06, 1.17, p<0.0001) were independently associated with the presence of NMOU during follow-up visits. Conclusions: 19% cancer patients followed at SCC had detectable NMOU behaviors. Being single, SOAPP+, pain severity and high MEDD were independent predictors for NMOU. This information will assist clinicians and investigators designing clinical and research programs in this important field.