A prospective, controlled study comparing the clinical results of the selective distal splenorenal shunt procedure and the side-to-side portacaval shunt procedure was undertaken in 1980. Ninety-three cirrhotic patients with previous episodes of bleeding from esophageal varices underwent a distal splenorenal shunt procedure (47 patients). The operative mortality rate was 2 percent in both groups. The intraoperative decrease of portal hypertension after the portacaval shunt procedure was higher than after the distal splenorenal shunt procedure (p less than 0.05), and in those with patent shunts, there was a 0 percent incidence of early variceal rebleeding after the portacaval shunt procedure compared with a 9 percent incidence after the distal splenorenal shunt procedure (p less than 0.05). Both shunts, however, had similarly satisfactory results in preventing long-term variceal rebleeding (portacaval shunt 2 percent and distal splenorenal shunt 0 percent). Postoperative ascites was more common after the distal splenorenal shunt procedure (58 percent versus 24 percent; p less than 0.01). Analysis of actuarial survival curves showed no difference between the two procedures. The incidences of long-term episodes of chronic encephalopathy were not statistically different after both procedures. The only three instances of severe encephalopathy occurred in patients with the portacaval shunt (p less than 0.05). The distal splenorenal shunt also seemed to have a less negative effect on postoperative liver function than the portacaval shunt. These data suggest that the selective shunt should be viewed as a first choice strategy in the treatment of portal hypertension.