This study introduces a novel approach to creating anti-biofouling surfaces using degradable polyphosphoester (PPE) polymer brushes. The brushes are synthesized via controlled surface-initiated organocatalytic ring-opening polymerization (SI-ROP) of cyclic phospholanes on silicon surfaces. Two monomers, 2-ethyl-2-oxo-1,3,2-dioxaphospholane (EtPn) and 2-hexyl-2-oxo-1,3,2-dioxaphospholane (HexPn), are used to prepare hydrophilic and hydrophobic brushes, respectively, with thicknesses up to 55 nm. The brushes exhibit enhanced resistance to protein adsorption, bacterial adhesion, and biofilm formation compared to non-coated surfaces and polyester brushes. The hydrophilic poly(2-ethyl-2-oxo-1,3,2-dioxaphospholane) brushes show significant reduction in albumin, fibrinogen, and diluted human serum protein adsorption, as well as in Escherichia coli and Staphylococcus aureus bacterial adhesion. The stability and anti-biofouling performance of these brushes make them attractive candidates for use in medical devices and artificial implant technologies. The study highlights the potential of PPE brushes as biodegradable alternatives to non-degradable polymers, addressing key challenges in biodegradability and effectiveness in antifouling applications.This study introduces a novel approach to creating anti-biofouling surfaces using degradable polyphosphoester (PPE) polymer brushes. The brushes are synthesized via controlled surface-initiated organocatalytic ring-opening polymerization (SI-ROP) of cyclic phospholanes on silicon surfaces. Two monomers, 2-ethyl-2-oxo-1,3,2-dioxaphospholane (EtPn) and 2-hexyl-2-oxo-1,3,2-dioxaphospholane (HexPn), are used to prepare hydrophilic and hydrophobic brushes, respectively, with thicknesses up to 55 nm. The brushes exhibit enhanced resistance to protein adsorption, bacterial adhesion, and biofilm formation compared to non-coated surfaces and polyester brushes. The hydrophilic poly(2-ethyl-2-oxo-1,3,2-dioxaphospholane) brushes show significant reduction in albumin, fibrinogen, and diluted human serum protein adsorption, as well as in Escherichia coli and Staphylococcus aureus bacterial adhesion. The stability and anti-biofouling performance of these brushes make them attractive candidates for use in medical devices and artificial implant technologies. The study highlights the potential of PPE brushes as biodegradable alternatives to non-degradable polymers, addressing key challenges in biodegradability and effectiveness in antifouling applications.