Parotid pleomorphic adenoma (PPA) is a benign tumor frequently found in parotid salivary gland. This tumor has various biological behaviors including recurrence after surgery, ability to transform into the malignant form, and occasionally, metastasizes to lymph nodes or other organs. For this PPA tumor, it is appropriate to look for alternative therapy forms other than surgery which is assumed to be the cause of the high tumor recurrence. Other alternatives may include hormonal therapy that needs baseline data on estrogen-receptor expression by PPA tumor cells. To collect the baseline data, a laboratory experimental retrospective study on immunohistochemical study using LsAB/labelled strepavidine-biotine technique of estrogen receptor (ER) receptor on 50 PPA tumor samples at the Anatomic Pathology Department of the Faculty of Medicine, Padjadjaran University/Hasan Sadikin General Hospital during 1998–1999 has been conducted. The observation is focused on the grouping of ER immunoexpression level spread by PPA tumor cells: 0=negative; +1=focal (>20%); +2=heterogeneous (20–50%); and +3=diffuse (>50% immunoreactive tumor cells). The results showed that 40/50 PPA tumor samples (80%) were immunoreactive towards ER with an immunoexpression composition of: 67.5% heterogeneous (27/40) and 32.5% diffuse (13/40). A homogenous smear pattern was observed in tumor cell nucleus. Ten cases showed negative results (8 cases negative and 2 cases focal). The positive PPA tumor tissue components included ductal /tubuloductal epithels, mixomatose and hypercellullar areas. In conclusion, PPA tumor plays the role as target of estrogen hormone and there is a high possibility that it is responsive to hormonal therapy.