Liver cysts are probably the most common incidental benign finding in the liver. They are “bags” of normal tissue fluid (“serous fluid”) contained by a thin wall. They come in variable numbers and sizes. Some patients may have numerous and/or large ones related to certain genetic conditions. Most liver cysts do not need treatment, but occasionally some do if they cause symptoms like pain or discomfort. Some cysts can be “complex” due to atypical features, and occasionally some cysts fall into the spectrum of pre-maligant tumours. These may need further investigations or treatment.