Morphometric parameters of carcinoma cells in 78 NPC and columnar epithelium basal cells in 21 of these 78 NPCs were measured by Quantimet 520 analyser. The results showed that: 1. Prominent enlargement of nuclei was a pathognomonic feature of carcinoma cells, except small spindle carcinoma cells, as compared with the normal basal cells, 2. vesicular nucleus cell carcinoma and small spindle poorly differentiated squamous carcinoma had their own characteristic morphometric parameters as compared with those of the ordinary poorly differentiated squamous carcinoma, and 3. there was no significant morphometric difference between vesicular nucleus cell carcinoma and poorly differentiated adenocarcinoma.