Sugar beet (Beta vulgaris L.) is supplying approximately 35% of sugar worldwide. It is the most important source of white sugar after sugarcane. It is so clear that pathogenic fungi are the main reason for enormous losses in sugar beet production. So this study aimed to focus on sugar beet deterioration caused by the infected fungi which affects sugar productivity in Egypt. Data indicated that fungal infection had a significant effect on reducing all growth parameters and total sugar content in infected sugar beet roots compared with healthy ones. A sum of 130 fungal isolates including 10 species were identified as Alternaria alternata, Aspergillus niger, Aspergillus parasiticus, Botrytis cinerea, Fusarium oxysporum, Fusarium solani, Penicillium spp., Rhizopus stolonifer, Rhizoctonia solani, and Sclerotium rolfsii. Mycotoxins analysis revealed that A. parasiticus isolate from the Sharqia governorate sample produced the highest concentration of total Aflatoxins (7319.69 ng/ mL), while the least concentration of total Aflatoxins produced by A. parasiticus isolate from Beni Suef governorate sample (5.18 ng/ mL). On the other hand, Aspergillus niger isolate from Sharqia governorate sample was able to produce 0.11 ng/ mL of Ochratoxin A, and Fusarium oxysporum isolate from sugar beet roots samples collected from Sharqia governorate produced the highest Fumonisin B1 concentration (8635.36 ng/ mL), while F. oxysporum isolate from Menofia governorate sample produced the least concentration (289.42 ng/ mL).It could be concluded that different toxigenic fungi can attack the sugar beet roots and cause their deterioration, which affects sugar productivity.