Epithelial benign salivary gland tumours are relatively uncommon and constitute a wide spectrum of variable morphologic & biologic entities. Among these cytological and morphological properties of salivary gland tumours, one of the most important criteria for measuring its biological behaviour approach is cell proliferation. The cell proliferation / death balance is most important in the development of salivary gland tumours. Aim of the study is to examine the expression of Bax mRNA gene using in situ hybridization technique & PCNA protein immunohistochemically. Twelve formalin fixed paraffin embedded tissue blocks of pleomorphic adenoma were used in this study. Haematoxylin and Eosin stain was used for reassessment of the histopathologic diagnosis. The cell proliferation activity was examined by proliferating cell nuclear antigen (PCNA)IHC and proapoptotic cell death Bax mRNA gene was analysed by ISH technique.The high proliferative rate could explain the natural course of PA benign & the decreased expression of bax indicate that loss of bax expression might give the tumour cells a double growth advantage because uncontrolled proliferation is combined with reduce cell death rate