Background: Intrahepatic cholangiocarcinoma (ICC) is a cancer of the bile ducts within the liver. Most patients have unresectable disease and die of tumor-related liver failure (TRLF); prior data suggest that radiation therapy (RT) may play an important role in decreasing TRLF and improving survival. However, for patients with exceptionally large liver tumors, the role of RT is uncertain. Here, we present our experience using hypofractionated RT for so-called “super-massive” ICC (gross tumor volume > 800cc). Methods: We retrospectively collected data from ICC patients treated at the University of Texas MD Anderson Cancer Center. We included inoperable patients (both M0 and M1) who were treated with RT, identified those with a gross tumor volume of 800cc or more (median: 1,300cc IQR: 900-1,900). We analyzed overall survival (OS), local and distant recurrence, tumor-related liver failure (TRLF), and treatment toxicity. Results: A total of 12 patients were included. The median age was 60 (IQR: 55-67). The average maximal tumor diameter was 14.1cm (IQR: 12.6-15.8). All but 1 patient received pre-RT systemic therapy. Eight patients (67%) were treated with IMRT, and 4 patients (33%) with proton RT. RT was delivered to a median of 67.5Gy (IQR: 60-73.1) over 15 fractions. At a median follow up of 17.4 months, 5 patients were still alive (2-year OS: 41.7%). Median OS, local recurrence, and distant metastasis from RT were 20.0, 20, and 11.3 months, respectively. Two patients (16.7%) died from TRLF. No grade 2 or higher toxicities were noted. No radiation-induced liver toxicity was present. Conclusions: Hypofractionated RT was safe and showed promising clinical outcomes for patients with “super massive” inoperable ICC, compared to historical data. Future studies are still needed to better assess the role of RT in this patient population.