Sixty primary untreated squamous cell carcinomas were studied for C-erbB2 gene amplification by non-fluorescence in situ hybridization technique. Amplified tumour cells showed intranuclear dark brown, often paired signals under light microscopy. Twenty-two out of 60 tumours (36.6%) showed signs of amplification of different degree (+ to +). Considerable heterogeneity of C-erbB2 amplification per cell was seen within each amplified tumour. The proportion of amplified cells ranged between 10 and 90% in these tumours. The arrangement of C-erbB2 in clusters in most amplified tumours suggests that C-erbB2 amplification occurs intrachromosomally. No significant difference in the frequency of amplification was observed according to clinical stage or the histological patterns of the tumours. The results of the present study showed frequent amplification of C-erbB2 in cervical carcinoma on paraffin sections. This technique was found to be more sensitive than the Southern blot technique which could detect amplification in 14% of the tumours of the same cohort.