OBJECTIVE To prospectively evaluate the ability for immunoscintigraphy with monoclonal antibody CYT-103 labeled with indium 111 to detect tumor presence in 15 patients with ovarian cancer undergoing second-look surgery. METHODS Prospective, open-label, nonrandomized trial. METHODS Hospital-based nuclear medicine facility and operating room. METHODS Patients with previous ovarian cancer scheduled for second-look surgery. METHODS Correctness of prediction of immunoscintigraphy for presence or absence of ovarian cancer compared with serum CA 125 titer and computed tomography. RESULTS Immunoscintigraphy, computed tomography, and serum CA 125 titer had respective sensitivities of 92%, 42%, and 42%; specificities of 67%, 100%, and 100%; accuracies of 87%, 53%, and 53%; and diagnostic values of 59%, 42%, and 42%. The full regional extent of recurrent tumor was correctly detected in 45% of patients by immunoscintigraphy and in none of the patients by computed tomography. Immunoscintigraphy detected miliary tumor in two of four patients and computed tomography, as expected, was unable to detect miliary disease. CONCLUSIONS Recurrent ovarian cancer often presents as multiple small lesions throughout the abdominal cavity. In this subset of patients, immunoscintigraphy may be particularly well suited for detection of the presence of recurrent tumor.