We analyzed regional heterogeneity of DNA content and of proliferative capacity. DNA-diploid as well as DNA-non-diploid tumour cell populations both were found to be present in 13% of the cases. The average coefficient of variation (CV) of DI appeared to be 2%. The CV's of G1PF, LI, and SPF, were 4%, 20%, and 25%, respectively. The CV's of Ts and for Tpot appeared to be 17% and 30%, respectively. The ratio of the intratumoural variability to the intertumoural variability, was lowest for DI. Intraobserver variability was evaluated. The correlation coefficient (CC) for LI and DI was 0.99 and 0.98, respectively, and for relative movement (RM) was 0.71. We concluded that for DI of head and neck tumours both representativity and reproducibility were better when compared with those for SPF, LI, G1PF, Ts, and Tpot.