On the basis of a group of 175 patients affected by liver cirrhosis and submitted to side-to-side porto-caval shunt, we have examined the presence of hypersplenism in 49.7% and its changes after splenectomy. In order to find out a suitable method to value the changes of the platelets, we observed platelet survival in seven patients either before or after porto-caval shunt. The results obtained encourage in affirming that: 1) Hypersplenism improves after a simple shunt. 2) Hypersplenism is not severe even if it persists with an open shunt. 3) The possible onset of shunt thrombosis worsens hypersplenism. 4) Platelet survival is surely effective in the study of hypersplenism.