The authors describe the examination, diagnostic possibilities and difficulties associated with the diagnosis of the spleen by means of computed tomography. The finding obtained by computed tomography is evaluated as splenomegaly when two of the three main dimension are greater than the maximal values reported, or when the lienal index is higher than 440. From the practical aspect the decision on splenomegaly is facilitated by the position of the anterior margin of the spleen in relation to the medioaxillary line. Splenomegaly is the most frequent pathological finding on the spleen. The authors give an account of causes of splenomegaly and their own experience with the diagnosis of anomalies, cystic processes, tumours, injuries and obstructions of the lienal vessels.