AIM--To investigate the distribution of cytokeratins 10, 13, 14 and 19 in biopsy specimens taken from acetowhite and non-acetowhite areas of the cervix. METHOD--Cervical biopsy specimens were taken from both acetowhite and non-acetowhite areas from 44 patients who presented with abnormal cervical cytology. The specimens were snap frozen in liquid nitrogen and multiple sections taken from each specimen. Staining was performed for cytokeratins 10, 13, 14, 19 and NADPH diaphorase enzyme. The areas of each section positive for the various markers were measured. RESULTS--Cytokeratin 10 positive cells were greatly increased in number in acetowhite biopsy specimens compared with non-acetowhite samples (45.1% v 2.8%; p < 0.0001). Cytokeratin 19 was also increased, but to a lesser extent (17.8% v 5.5%; p < 0.0001). In contrast, the almost universal expression of cytokeratin 13 was reduced in acetowhite biopsy specimens (86.2% v 96.9%; p < 0.0001). Cytokeratin 14 was found diffusely in the basal region of the stratified squamous epithelium and was marginally more apparent in the acetowhite biopsy specimens (p = 0.04). CONCLUSION--It is suggested that the presence of cytokeratin 10 may be an essential requirement for the formation of acetowhite change in association with the cellular swelling caused by acetic acid.