Living　organisms　produce　a　myriad　of　molecules　to　protect　themselves　from　fungal　pathogens.　This　review　focuses　on　antifungal　proteins　from　plants　and　mushrooms,　many　of　which　are　components　of　the　human　diet　or　have　medicinal　value.　Plant　antifungal　proteins　can　be　classified　into　different　groups　comprising　chitinases　and　chitinase-like　proteins,　chitin-binding　proteins,　cyclophilin-like　proteins,　defensins　and　defensin-like　proteins,　deoxyribonucleases,　embryo-abundant　protein-like　proteins,　glucanases,　lectins,　lipid　transfer　proteins,　peroxidases,　protease　inhibitors,　ribonucleases,　ribosome-inactivating　proteins,　storage　2S　albumins,　and　thaumatin-like　proteins.　Some　of　the　aforementioned　antifungal　proteins　also　exhibit　mitogenic　activity　towards　spleen　cells,　nitric　oxide　inducing　activity　toward　macrophages,　antiproliferative　activity　toward　tumor　cells,　antibacterial　activity,　and　inhibitory　activity　toward　HIV-1　reverse　transcriptase.　In　contrast　to　the　large　diversity　of　plant　antifungal　proteins,　only　a　small　number　of　mushroom　antifungal　proteins　have　been　reported.　Mushroom　antifungal　proteins　are　distinct　from　their　plant　counterparts　in　N-terminal　sequence.　Nevertheless,　some　of　the　mushroom　antifungal　proteins　have　been　shown　to　inhibit　HIV-1　reverse　transcriptase　activity　and　tumor　cell　proliferation.　©　2010　Springer-Verlag.