Peritoneal metastases from gynecologic and gastrointestinal cancer is of increasing interest to surgical and medical oncologists because of newly recognized benefits of treatment. In contrast to prior outcomes, prolonged disease-free survival and cure have been reported. To date, the benefits are to use complete surgical removal of the peritoneal metastases combined with hyperthermic intraperitoneal chemotherapy (HIPEC) delivered in the operating room. To supplement the local-regional control, normothermic intraperitoneal chemotherapy used long term (NIPEC-LT) and delivered by an intraperitoneal port has been explored. In three high grade malignancies with the preponderance of cytoreductive surgery (CRS) and HIPEC treatment failures within the peritoneal space, NIPEC-LT has been favorably reported in the oncology literature. In ovarian cancer and malignant peritoneal mesothelioma the NIPEC-LT is used an adjuvant treatment in an attempt to preserve a surgical complete response of CRS. In gastric cancer, NIPEC-LT is given as a neoadjuvant treatment with responders going on to radical surgical resection. Responses are monitored by laparoscopy. This overview highlights benefits of NIPEC-LT in three diseases where benefits from CRS and HIPEC have been recognized but that local-regional failures persist. Improved results with NIPEC-LT have been reviewed for ovarian cancer, gastric cancer, and peritoneal mesothelioma.