81 Background: While depression is often under-diagnosed in the general population, the rate of under-diagnosis among patients with cancer may be far higher. The American Cancer Society reports that a quarter of all patients with cancer may suffer from depression. We seek to identify a link between pain and depression among patients with cancer which may signal an enhanced need both for the involvement of mental health services and for more effective pain management. METHODS This is an observational cross-sectional study evaluating depression among patients with cancer in an outpatient setting. From June of 2015 to January of 2016, 29 patients from our institution's affiliated cancer clinics were interviewed by study staff members about their pain and various other cancer-related concerns. Subjects were also administered the depression screening tool Patient Health Questionnaire 9 (PHQ-9). Data was collected and analyzed using Spearman's rho. RESULTS The inclusion criteria included a confirmed cancer diagnosis and willingness to participate in a clinical study. There were no exclusion criteria. Age ranged from 43 to 87 and women comprised 75% of participants. Of the 18 patients who complained of pain (62.1% of the total), 14 reported pain of at least 7 of 10 in severity (77.8%). Severity of pain was found to correlate positively with the questions of "Poor appetite or overeating" as well as "Moving or speaking so slowly...Or the opposite - being so fidgety or restless..." (R = 0.41, P = 0.03; R = 0.40, P = 0.03, respectively). Presence of pain likewise correlated positively with the latter question (R = 0.46, P = 0.01). CONCLUSIONS The effects of depression on patients with cancer may contribute to life-shortening complications related to reduced compliance with treatment and lifestyle modifications, as well as the exacerbation of heart disease and other comorbid conditions. Our findings demonstrate that pain, particularly severe pain, may signal an elevated risk of depression and call for the swift involvement of mental health services. Likewise, the high proportion of patients complaining of pain in general and severe pain in particular suggests a need for more aggressive pain management among patients with cancer within our cohort.