Ipilimumab is a promising novel immunotherapy agent and is associated with a variety of immune-related adverse events (irAE). The purpose of this study was to investigate the manifestations of irAEs on body imaging in patients with advanced melanoma treated with ipilimumab. One-hundred forty-seven patients with advanced melanoma (59 women, 88 men; median age, 64.5 years) treated with ipilimumab were studied. All patients had the baseline and at least one follow-up chest/abdomen/pelvis CT or PET/CT during therapy, which were reviewed by a consensus of two radiologists blinded to the clinical data. Findings indicative of individual types of irAEs were assessed, including thyroiditis, sarcoid-like lymphadenopathy, pneumonitis, hepatitis, pancreatitis, and colitis. Among the 147 patients, 46 (31%) had radiologically identified irAEs. The time interval from the initiation of therapy to the development of irAEs was less than 3 months in 76% (35 of 46) of the patients (range, 0.2–9.1 months). Clinical characteristics did not differ between patients with and without irAEs (P > 0.18). Among the individual types of irAEs, colitis was most common (n = 28; 19%), followed by sarcoid-like lymphadenopathy (n = 8; 5%) and pneumonitis (n = 8; 5%). Hepatitis (n = 3), thyroiditis (n = 2), and pancreatitis (n = 1) were less common. The resolution of irAEs was noted in 32 of 36 patients (89%) with further follow-up scans, with a median time of 2.3 months after the detection of irAE. In conclusion, irAEs were noted on body imaging in 31% of patients with melanoma treated with ipilimumab. Colitis was the most common, followed by sarcoid-like lymphadenopathy and pneumonitis. The results call for an increased awareness of irAEs, given the expanding role of cancer immunotherapy. Cancer Immunol Res; 3(10); 1185–92. ©2015 AACR.