Published studies have reported widely variable incidence of HER2/neu (c-erbB-2) protein expression and HER2/neu (c-erbB-2) gene amplification in cervical carcinoma. We examined tissue microarrays (TMAs) constructed from 814 formaldehyde-fixed paraffin-embedded archival specimens of cervical intraepithelial neoplasia (CIN)1 (n = 262), CIN2 (n = 230), CIN3 (n = 186) and invasive carcinoma (n = 136), for HER2/neu protein expression by immunohistochemistry (IHC) and for HER2/neu gene amplification by chromogenic in situ hybridization (CISH). We found moderate or strong immunohistochemical positivity for HER2/neu in 64 of 814 specimens (7.9%). Using CISH, polysomy of the HER2/neu gene was detected in 87 cases (10.7%), low/borderline amplification in five cases (0.6%) and true amplification in four cases (0.5%). The correlation between IHC and CISH was statistically significant in CIN2, CIN3 and invasive cervical carcinoma specimens. When present, Her-2/neu positivity is more commonly seen in higher grades of cervical dysplasia and in carcinoma. However, this large TMA study shows that HER2/neu oncoprotein expression and HER2/neu gene amplification overall are uncommon events in cervical neoplasia. This provides compelling evidence that HER2/neu plays no major role in the development and progression of cervical neoplasia.