The standard definition of platinum-resistant ovarian cancer or primary peritoneal carcinoma commonly includes patients whose disease initially responded to a platinum-based combination regimen, but recurred less than 6 months after the completion of primary therapy. Recent experience with several patients with these malignancies treated in the Gynecologic Cancer Program of the Cleveland Clinic Foundation, whose disease recurred within this period but who subsequently responded to platinum therapy, calls into question the validity and clinical relevance of this commonly employed definition, both for the conduct of phase 2 trials of new agents in ovarian cancer and primary peritoneal carcinoma, and for the standard management of women in this clinical setting.