Nucleolar organizer regions (NORs) were studied in surgically removed specimens from 76 patients with squamous cell carcinomas of the larynx using an argyrophilic (Ag) staining technique. The mean number of AgNORs per nucleus was 4.3 +/- 1.38 (SD). The mean AgNOR number for T1 or T2 disease was statistically lower than that for T3 or T4 lesions (P < 0.05). The mean AgNOR number was lower in patients with N0 disease than in patients with N1 or N2 or N3 tumors (P < 0.05). There was also a statistically significant difference between the mean AgNOR number for stage II and stage III disease (P < 0.01), for stage III and stage IV disease (P < 0.05), but not for stage I and stage II disease. According to the histological grading, there was a significant difference between the mean AgNOR number for the well-differentiated and moderately differentiated tumors (P < 0.05), and for the moderately differentiated and poorly differentiated types (P < 0.01). These results suggest that the number of AgNORs in the nucleus is a significant indicator of laryngeal carcinomas.