Objective(s): The Gynecologic Oncology Group (GOG) examined the association between ERBB2 amplification and clinical covariates, tumor response, disease status post-chemotherapy, progression-free survival (PFS), and overall survival (OS) in epithelial ovarian cancer (EOC). Methods: Women with suboptimally-resected, advanced stage EOC who participated in GOG-111, a multi-center randomized phase III trial of cyclophosphamide + cisplatin versus paclitaxel + cisplatin, and provided a tumor block through the companion protocol GOG-9404 were eligible. ERBB2 amplification was examined using fluorescence in situ hybridization (FISH) with probes for ERBB2 and the centromere of chromosome 17 (CEP17). Results: ERBB2 amplification, defined as > 2 copies of ERBB2/CEP17, was a rare event in EOC with 7% (9/133) of women exhibiting between 2.2 and 33.7 copies of ERBB2/CEP17, and was not associated with patient age, race, GOG performance status, stage, cell type, grade, measurable disease status, volume of ascites, tumor response or disease status post-chemotherapy. Women with > 2 verses ≤ 2 copies of ERBB2/CEP17 did not have a reduced risk of disease progression (hazard ratio [HR] = 0.56; 95% confidence interval [CI] = 0.27-1.16; p = 0.120) or death (HR = 0.57; 95% CI = 0.26-1.23; p = 0.152), and ERBB2 amplification was not an independent prognostic factor for PFS or OS. ERBB2 amplification, defined as > 4 copies of ERBB2/nuclei, was observed in 9% (12/133) of women with levels ranging from 4.2 to 49.2 copies of ERBB2/nuclei, and was associated with older age and volume of ascites, but not with the other clinical covariates or outcome. Conclusion(s): ERBB2 amplification is a rare event and has no predictive or prognostic value in suboptimally-resected, advanced stage EOC treated with platinum-based combination chemotherapy. © 2009.