A brief overview of the aetiopathogenetic aspects of non-parasitic cyst of the liver is followed by the presentation of two personal cases. Their diagnostic, anatomopathological and therapeutic features are examined, and reference is made to the treatment employed, namely partial cystectomy and derivation on an excluded loop à la Roux. It is suggested that the type of surgery employed will depend in each case on the relation of the cyst to the liver parenchyma (superficial or deep sites) and neighbouring organs. Benign forms should be treated in a not excessively destructive manner.