Chronic genital edema secondary to lymphangiectasia and chylous reflux in a 23-yr-old man with Noonan syndrome was investigated by 99mTc sulfur nanocolloid lymphoscintigraphy and bipedal contrast lymphangiography. Lymphoscintigraphy showed a delayed lymphatic flow pattern in the pelvis, abdomen and chest consistent with lymphangiectasia and abnormal lymphatic flow dynamics. Lymphangiography showed dilated and tortuous abnormal lymphatics in the abdomen and pelvis. Ligation of incompetent retroperitoneal lymph vessels and lymphaticovenous anastamosis were performed, resulting in clinical improvement. Lymphangiectasia has been described previously in Noonan syndrome, but it is relatively uncommon below the diaphragm. This case demonstrates the use of lymphoscintigraphy and lymphangiography in providing important physiological and anatomical information before surgical intervention. Careful presurgical planning using such tests also allows the most appropriate operation to be performed.