The Known prognosticators of adenoid cystic carcinomas are primary sites, clinical stages and histopathologic patterns. But the prognosis cannot be estimated directly from the histopathologic patterns because usually the three components(tubular, cribriform, solid) are all mixed up in one tumor. Argyrophilic nucleolar organizer regions(AgNORs) reflect the proliferative activity of the tumor cells and are closely related to the DNA contents and proliferation index(PI) by cell cycle analysis. The aim of this study is to observe whether or not the number of AgNORs and PI are correlated with the histopathologic types and recurrences. The authors performed silver staining for nucleolar organizer regions and image analysis for DNA contents in 19 cases of adenoid cystic carcinomas during the recent 10 years. The obtained results are summarized as follows : 1) The mean number of AgNORs in adenoid cystic carcinomas(5.80±1.88) was significantly higher than that in benign lesions(2.06±0.53)(p<0.01). 2) The mean number of AgNORs in case of recurrences or distant metastasis(6.39±1.96) was significantly higher than that in cases without recurrences or distant metastasis(4.98±1.51)(p<0.01). 3) The mean number of AgNORs and the mean value of PI were proven to be significantly correlated(r=0.768, p<0.01). 4) The more aggressive histopathologic types containing more solid components, the higher the mean number of AgNORs(Type Ⅰ 5.13±1.64, Type Ⅱ 6.14±1.84, Type III 6.33±2.75) and the PI showed the same tendency(Type I 16.60±1.27, Type II 29.39±2.34, Type Ⅲ 31.81±2.98)(p>0.01). In conclusion, the mean number of AgNORs and PI appear to be of value in estimating the proliferative activity of tumor cells and they are considered as significant prognosticators in adenoid cystic carcinomas of the salivary glands.