Conflict exists with respect to the type of pleomorphic adenoma (PA) most likely to recur and whether the possibility of recurrence can be determined by the histology of the lesion. In this study, specific clinical, histological features and treatment modalities were examined in 53 intra-oral PA's with respect to their relevance to the diagnosis and prognosis. No correlation was found between the duration of symptoms and the proportion of stroma in the PA's nor was there any correlation between the size and the duration. However, at the time of diagnosis, the stroma-poor tumours had attained a significantly larger size than the stroma-rich tumours. This may suggest that the cellular tumours grow at a faster rate. Hyaline cells were shown to be a distinct feature of intra-oral PA's, especially in the stroma-poor subtypes. The proportion of the stroma and the capsule integrity do not seem to influence the prognosis. Follow-up information was obtained for 51% of the patients, and despite the fact that the majority of the lesions (33/53) were treated by excisional biopsy, no recurrences were reported. The follow-up period ranged from 0.6 to 12.6 years (mean 5.3 years).