The chromosomal telomeric association in peripheral blood lymphocytes from 25 untreated patients with nasopharyngeal carcinoma (NPC) and in NPC cell lines (CNE) was investigated by using chromosome G banding technique. The cell telomeric association rate of patients (35.07%) was found to be higher than that of controls(20.27%) (P < 0.01), while in the two groups the distributions of chromosomes involved were approximately the same (P > 0.05). The telomeric association rates of patients were significantly higher than those of control in chromosomes 1, 2, 3, 4, 7, 11, 15, and 17(P < 0.05). In NPC lines (CNE), 94% of the cell division phases showed telomeric association. Chromosomes 2, 3, 5, 11 and 16 had higher frequencies of association than other chromosomes. The most frequent telomeric association was single chromatid association.