Malignant melanoma (MM) is associated with significant morbidity and mortality, and MM cases worldwide are increasing faster than any other cancer. Patients with inflammatory bowel diseases (IBD) are known to be at increased risk of non-melanoma skin cancer (NMSC) due to abnormalities in innate immunity, immunosuppressive medications, or both. However, little is known about the overall risk, clinical characteristics, and course of MM in patients with IBD. We sought to describe clinical characteristics of MM in patients with IBD, and evaluate whether these characteristics differ over time, by patient age, and concurrent use of immunosuppressive medications. At 2 tertiary care centers, University of North Carolina and Duke University Medical Center, we identified patients with at least 1 ICD-9 code for both melanoma (172.x or V10.82) and IBD (555.x and 556.x), and reviewed clinical records to confirm these diagnoses. Those without definitive diagnosis of MM of the skin or IBD were excluded. Characteristics of the MM, such as site, depth, and therapy, as well as characteristics of the IBD, such as duration of disease, type of IBD, and medication use, were abstracted from the medical record. Descriptive statistics and bivariate analyses were used to compare characteristics by age, by time, and by immunosuppressive medication use at the time of MM. A total of 80 patients were included. The median age at the time of melanoma was 51 (IQR 38-65), median age of IBD diagnosis was 43 (29-58). The population was 42.5% female. A total of 42.5% had Crohn's disease (CD), 53.7% had ulcerative colitis (UC), and 3.8% unknown type. Immunosuppressive medications (thiopurine, methotrexate, or biologic) were used at the time of MM in 24.2% of patients. When compared to the United States population with melanoma, as reported in Surveillance and End Epidemiology Results (SEER) database, patients with IBD were younger at the time of MM diagnosis. Sites of MM in the IBD population included 26.0% head/neck, 44.2% trunk, 13.0% upper extremity, 16.9% lower extremity, 18.2% metastatic at presentation. Those on immunosuppression at the time of MM diagnosis were significantly younger than those not on immunosuppression (42.6 v. 53.2, p=0.03). When comparing those in the youngest quartile of age at MM diagnosis to others, younger patients had significantly fewer in-situ melanomas (9.1% v. 40.4%, p=0.05). When melanoma was evaluated by year of diagnosis, subjects diagnosed after 2000 were diagnosed with melanoma at an older age (56.5 v. 40.0, p=0.02), their therapy more often included sentinel node biopsy (p<0.01), and a higher percentage were on immunosuppression (32.6 v. 7.1, p=0.06). This large, multi-institutional case series suggests that MM may develop earlier in life in IBD patients, as compared with the general population, particularly in patients treated with immunosuppressive medications. Additionally, in our series, melanomas diagnosed early in life were more often deeper than melanomas occurring in older individuals. As sunscreen use has been shown to prevent melanoma and reduce nevi development in children, counseling on sun protection at an early age may be indicated.