The　performance　degradation　of　proton　exchange　membrane　fuel　cells　(PEMFCs)　is　one　of　the　most　critical　challenges　in　their　practical　applications.　Degradations　of　electrocatalysts　for　oxygen　reduction　reaction　(ORR)　at　cathode　and　hydrogen　oxidation　reaction　(HOR)　at　the　anode　are　the　major　contributors　to　PEMFC　degradation,　which　are　mainly　induced　by　fuel/air　impurities,　unintentional　harmful　species　during　the　preparation　and　use　of　the　catalysts,　as　well　as　catalyst　decomposition　during　the　operation.　This　review　summarizes　the　recent　research　on　PEMFC　performance　degradation　and　the　progress　in　developing　mitigation　strategies　for　avoiding　the　degradation.　Several　aspects　are　emphasized　as　follows:　the　understanding　of　catalyst　poisoning　phenomena,　influencing　factors,　and　general　degradation　mechanisms.　Several　technical　challenges　are　analyzed　and　the　corresponding　future　research　directions　are　proposed　to　facilitate　the　further　research　and　development　of　mitigation　strategies　for　PEMFC　catalyst　degradation.　©　2021　Elsevier　Ltd