Hepsin is a type II transmembrane serine protease (TTSP) that plays a crucial role in cell growth and development. Hepsin is highly expressed in prostate cancer (PCa) and associated with its progression and metastasis. Therefore, it has been considered as an attractive biomarker of PCa. Recently, low molecular weight inhibitors targeting hepsin have been developed. Based on the key chemical scaffold, they can be classified into four classes: Indolecarboxamidines, benzamidines, peptide-based analogs, and 2,3-dihydro- 1H-perimidines. In this review, we discuss design strategy, structure-activity relationship (SAR), and binding mode of the four classes of hepsin inhibitors.