In light of the poor prognosis for ovarian cancer, research continues for innovative and efficacious treatment modalities. It is now widely accepted that new approaches for the treatment of ovarian cancers are pivotal to further improve the prognosis of this disease. We investigated the role of HAI-1 and HAI-2, and evaluated their clinical importance in ovarian cancer. The distribution of cases that scored positive for each of the biological parameters examined was correlated with HAI-1 and HAI-2 expression status obtained by immunohistochemistry. There was a significant correlation between HAI-2 expression and stage (p=0.031), amount of ascites (p=0.002) and diameter of residual tumor (p=0.034). HAI-1 expression was a significant associated with stage (p=0.040). Furthermore, the low HAI-1 and HAI-2 expression was a significant predictor for poor prognosis when compared with high HAI-1 and HAI-2 expression (disease-free survival rate; p=0.031 and p=0.003, overall survival rate; p=0.048 and p=0.001). Therefore, we investigated biological functions and effects of HAI-1 and HAI-2 using OVCAR-3 ovarian cancer cell lines. HAI-1 and HAI-2 show potential inhibitory effects mediated by reduction of matriptase and hepsin expression which leads to apoptosis through increasing the level of Bak and reducing the level of Bcl-2 on ovarian cancer. These findings indicate that low HAI-1 and HAI-2 expression in ovarian cancer may be associated with poor prognosis. HAI-1 and HAI-2 could be considered a therapeutic target for treatment approaches in ovarian cancer.