Cyfra 21-1 is a recognised marker for epidermoid lung and head and neck carcinomas oriented to the cytokeratin 19 that is expressed particularly in malignant epithelial cells. The aims of this study were to evaluate the importance of the use of this marker in nasopharyngeal carcinoma (NPC). Our prospective study interested 41 patients (33M/8F) with a mean age of 44 years (13 to 70) with 8 of them aged less than 30 years, presenting a nasopharyngeal carcinoma histologically confirmed from September 1999 to March 2000 and 45 healthy controls without evidence neoplasm. Undifferentiated forms represent 90.2% of cases and lesions are staged T2, T3 and T4 in 2.4%, 36.6% and 61% of cases, while N1, N2 and N3 represent 9.8%, 26.8% and 41.5% of cases. A blood sample was collected from each patient and control before any treatment, as well as controls to measure Cyfra 21-1 by immunoenzymatic assay, 2 groups of patients were selected after a period varying from 4 to 37 months with a median of 29 months: 27 patients with favourable evolution (without evidence of disease after initial treatment), 12 patients with non favourable evolution (1 death, 2 cases of loco-regional relapse and 9 patients with metastatic disease). 2 patients were lost to follow-up. The results showed that the mean serum Cyfra 21-1 values were significantly higher in patients with NPC than those in controls (p = 0.001). A significant correlation was found between the serum Cyfra 21-1 level before treatment and the clinical outcome of patients (p = 0.0009). Patients having a favourable evolution have the lowest level. Seric level of Cyfra 21-1 at diagnosis of NPC may play a predictive role to evaluate the risk of metastatic disease and prognosis.