Background: Ovarian mucinous carcinoma has a poor prognosis in advanced stages and a poor response to conventional chemotherapy. An efficient treatment is not yet available. We heere investigated HER2 expression and the potential for trastuzumab therapy in ovarian mucinous tumors. Materials and Methods: Immunohistochemistry was performed in formalin-fixed, paraffin-embedded tissue from 27 ovarian mucinous tumors including 14 carcinomas and 13 borderline tumors diagnosed in the Pathology Department, Farhet Hached Hospital, Sousse, between 1993 and 2013. The HercepTest (DAKO) was used for immunohistochemistry. Results: HER2 expression was observed in only one borderline tumor (7.7%) and in 14.3% of mucinous carcinomas of the ovary. Conclusions: Our results suggest that trastuzumab therapy would be an option for patients with mucinous carcinoma when the tumor has HER2 overexpression.