Among adults, liver involvement is relatively frequent in Langerhans’ cell histiocytosis (LCH), even though it is often overlooked. In fact, the liver involvement may be missed in apparently localized LCH or when it is the sole site of involvement. We present 23 cases of liver involvement in LCH out of a cohort study of 85 adult patients included in the French Histiocytosis Study Group Registry. The most frequent clinical setting was multiorgan involvement (87% of our cases). The main histological pattern in liver LCH was sclerosing cholangitis (56% of the cases). The symptoms included hepatomegaly (48%) and/or liver biochemistry abnormalities (61%, including cholestasis associated with increased transaminases levels in 35% of cases, cholestasis only in 22% and increased transaminases levels only in 4% of the cases). Particularly suggestive of the diagnosis was the observation of biliary tree abnormalities through magnetic resonance imaging (MRI). The natural history of liver LCH fits into two stages: early infiltration by histiocytes and late sclerosis of the biliary tree. We found that liver involvement had a significant impact on survival. Thus we suggest that clinical and biological liver evaluation must be performed regularly onwards to screen every LCH adult patient from the time of the initial diagnosis. MRI and liver biopsy should be considered as soon as the data point to a possible liver localization. If this diagnosis is confirmed, we suggest a treatment with ursodesoxycholic acid, as in other cholestatic diseases, together with treatments specifically directed towards LCH. However, the ideal treatment of liver LCH remains to be found, and in advanced cases transplantation is the sole option.