The levels of prostaglandins E, E2 and F2a (PGE, PGE2, PGF2a) in plasma of NPC patients, patients with other tumors and normal individuals were monitored by radioimmunoassay. The results showed that PGE and PGE2 levels in the plasma of NPC and other cancer patients were significantly higher but the PGF2a/PGE2 ratio was obviously lower than that of the normal (P less than 0.05). But there were not much changes in the PGF2a levels (P greater than 0.05). However, no difference was found between the PG8 levels of the NPC and the other cancer patients (P greater than 0.05). Neither were there any significant changes in the PGE2 and PGF2a plasma levels and ratio of PGF2a/PGE2 in 26 NPC patients staged according to TNM classification. It is indicated that there is a relation between PGE, PGE2 and nasopharyngeal carcinoma.