Background: Non-Medical opioid use is a growing crisis. Cancer patients at risk of harmful use of prescribed opioids are frequently underdiagnosed. The aim was to develop a nomogram to predict the probability of occurrence of Inappropriate opioid use that is, presence of SOAPP ≥ 7) among patients receiving outpatient supportive care consultation at a comprehensive cancer center. Methods: 3588 consecutive cancer patients referred to a supportive care clinic from March 1, 2016 to July 15, 2018 were reviewed. Patients were eligible if they had diagnosis of cancer, and were on opioids for pain for at least a week. All patients were assessed using Edmonton Symptom Assessment Scale with spiritual pain and financial distress (ESAS-FS), MEDD (morphine equivalent daily dose), SOAPP-14 (validated questionnaire for assessment of risk of inappropriate opioid use, and CAGE-AID (screening questionnaire for alcoholism/substance use disorder). Patients at with SOAPP+ were defined by SOAPP score ≥7. A nomogram was devised based on the risk factors determined in the multivariate logistic regression model and it can be used to estimate the probability of inappropriate opioid use. Results: Median age was 62yrs. Median ESAS pain item score on consultation was 5, Median ECOG was 2.20.4% were SOAPP+ and 10.1% were CAGE-AID+. SOAPP+ was significantly associated with gender, race, marital status, smoking status, depression, anxiety, financial distress, MEDD and CAGE score. The C-index is 0.8(CI 0.78, 0.82). A nomogram was developed. For example, for a male Hispanic patient, who is married, never smoked, with the following ESAS scores: (depression = 3, anxiety = 3, financial distress = 8), CAGE score of 0, and MEDD of 20, the total score is 9+9+0+0+6+10+26+0+1 = 61. In the nomogram a score of 58 indicates the probability of inappropriate opioid use being 0.1 and a score of 88 indicates the probability of 0.2. Based on the patient’s total score of 61, the probability of his aberrant behavior is between 10% to 20% (close to 10%). Conclusions: A nomogram can predict the risk of inappropriate opioid use in cancer patients.