It has been reported that DNA content analysis provides prognostic information eliminating the subjective component involved in routine microscopic decision making. In an attempt to establish a relationship between pathological findings and flow cytometric analysis, 36 formalin-fixed, paraffin-embedded tumour tissue samples were prepared according to Hedley's method and analysed by means of an Epics Profile II flow cytometer. DNA aneuploidy was observed in 15 tumours (41%). A statistically significant correlation was identified between DNA index and mitoses, cellular response and degree of differentiation, but not the ploidy status. It was not possible to identify a significant association of sex, age, and site of the tumour to DNA index. We found a strong correlation between histologic malignancy and DNA index; an increase in DNA index as malignancy score increases was noted. It was concluded that DNA index shows a good correlation with the histologic features of oral cancer, being a complement of differentiation and histologic grading analysis. The use of DNA analysis as a complement to pathological studies would help to diminish the subjective component of assessment of head and neck cancers. Ploidy status was not statistically associated with the differentiation of tumours.