Ovarian cancer spreads to multiple areas of the peritoneal cavity early in the course of the disease. Multiple small foci of tumor are not identified readily with standard preoperative staging procedures. A review of an immunoscintigraphy study of more than 100 women preoperatively staged with 111In-labeled B72.3 (CYT-103) reveals that this technique has a low potential for serious side effects and it can identify miliary spread of ovarian cancer and extra-abdominal metastases. It has the potential to contribute favorably to patient management by detecting occult lesions, may define the extent of tumor as well or better than computerized tomography and may impact on surgical decision-making.