Jun and Fos proteins form the transcription factor activating protein 1 (AP-1). They play a role in cell proliferation, malignant transformation and invasion in various tumors. The aim of the current study was to characterize the role of AP-1 in ovarian cancer. Fifty-six ovarian tumors of different invasive potential including 13 metastases as well as 5 ovarian cancer cell lines were analyzed by Western blot analysis regarding their expression of pc-Jun, Jun B, Jun D, c-Fos, Fos B, Fra-1 and Fra-2. In addition, invasion, cell proliferation and migration assays were performed. The expression of pc-Jun, Jun B, Jun D and Fra-2 was higher in invasive cancer compared to benign tumors. In metastases, c-Fos and Fos B expression was significantly lower than in the respective primary ovarian carcinomas. The invasive and proliferative potential of the cells was not associated with AP-1 protein expression. These results suggest that AP-1 proteins are differentially expressed in benign ovarian tumors, tumors with low malignant potential and epithelial ovarian carcinomas and metastases. No correlation with the proliferative and invasive potential of ovarian cancer cell lines could be found.