Protein tyrosine phosphatases (PTPs) and their inhibitors have been more and more studied during the past decades. Dephosphorylation is implicated in many biological events including the progression of the cell cycle. Around two hundred PTPs are known in humans, divided into three main groups. They all have a common amino acid sequence in their active site, referred to as the C(X)5R motif, namely a cysteine followed by five varying residues and an arginine. The CDC25 and CDC14 families are examples of PTPs described for their potential in cancer treatment, since they are key regulators of the cell cycle progression. CDC25 inhibitors have already proved their antiproliferative properties whereas the effect of the inhibition of CDC14 remains to be studied.The current review describes how the homology of the active site among the PTPs leads to similarities in their mechanism of action, regulation and inhibition. These similarities make it possible for medicinal chemists to design inhibitors based on the knowledge acquired on PTP1B inhibitors.