Although hepatic cysts occur in 34-75% of patients with polycystic kidney disease (PKD), infection of hepatic cysts is rare. The detection of infected hepatic cysts in PKD presents diagnostic and therapeutic difficulties, especially when a focus of infected cysts exists with innumerable uncomplicated cysts. The authors describe a 44-year-old woman with PKD who had recurrent infected hepatic cysts that were previously treated with percutaneous drainage and antibiotics. CT revealed innumerable hepatic cysts, but no discrete focus of hepatic infection. An In-111 WBC scan, however, demonstrated intense uptake in the right superior posterior hepatic lobe, consistent with infected hepatic cysts. The patient underwent partial resection of the right hepatic lobe. The patient had no evidence of hepatic infection since resection. A postoperative In-111 WBC scan demonstrated normal uptake in the liver. The In-111 WBC scan not only identified the precise location of the infected hepatic cysts, but also confirmed their complete resection.