Upper- and lower-extremity lymphoscintigraphy was performed on 50 patients with proven carcinoma of the breast, gastrointestinal system, genitourinary tract, lung, and vulva; 42 patients had 131I-antibodies to carcinoembryonic antigen (CEA) and 8 patients had 131I-normal goat immunoglobulin G. All metastases in the axillary or inguinal lymph nodes were detected with the CEA antibodies. In nine patients without metastases, radioactivity was observed in inguinal or axillary nodes. It is postulated that the nodal sequestration of antibody in the absence of metastatic carcinoma is due to captured CEA in lymph nodes draining the tumor site. This study has demonstrated the high sensitivity for detecting nodal metastases by labeled antibodies to CEA draining from primary or recurrent tumors.