Monitoring of peritoneovenous Le Veen shunt by duplex ultrasonography was first performed in 1993 in 10 patients. The duplex signal was picked up selectively in the venous tube and the peak velocity was measured at forced inspiration. Thirty-two examinations were performed. Of these, 13 had follow-up examinations by other modalities (radionuclide imaging, shuntography, or surgical exploration), all of which confirmed the findings of duplex ultrasonography. Shuntography was avoided in all instances with a patent shunt. Duplex ultrasonography allows noninvasive assessment of Le Veen shunt patency and appears reliable for determining the need for invasive diagnostic modalities or surgical shunt correction.