Stevia was introduced as a medicinal crop to Egypt in 1990 as a source of natural sweeteners for low-energy foods. Soilborne diseases such as southern blight (Sclerotium rolfsii Sacc.), charcoal rot (Macrophomina phaseolina (Tassi) Gold.), wilt (Fusarium oxysporum Schlecht. emend. Snyd. & Hans.), and root rot (F. semitectum Berk. & Ray., F. solani (Mart.) Appel & Wr. emend. Snyd. & Hans., and R. solani Kühn), as well as airborne diseases like black spot (Alternaria steviae Nees ex Wallr.) and gray mold (Botrytis cinerea Pers. ex Fr.), have been recorded for the first time on stevia plants grown in Giza Governorate. Isolation from infected roots and basal stems revealed that S. rolfsii is the most frequent, followed by F. oxysporum and R. solani. Pathogenicity tests indicated that the fungi isolated are pathogenic to stevia, causing symptoms similar to natural infections. S. rolfsii was the most virulent fungus, attacking the plants and affecting their growth (plant height, number of branches, and fresh weight), followed by F. oxysporum, M. phaseolina, and R. solani. The efficacy of Topsin M and Vitavax/Thiram (3 gm/kg seed or in water), as well as Plant Guard (3X10^7 cfu of T. harzianum; 4 ml/kg seed or in water) and Rhizo N (3X10^7 cfu of Bacillus subtilis, 4 gm/kg seed or in water) as seed dressing and dip treatment for seedlings in controlling soilborne diseases was evaluated. Significant reductions in infection are consistently achieved by using fungicides, while similar results are recorded in most cases with biocides. Topsin M is the most effective against most soilborne fungi, while Plant Guard is superior specifically for F. oxysporum. The ineffective treatments are Plant Guard against R. solani and S. rolfsii (seed dressing), S. rolfsii (dip treatment), and Rhizo N against R. solani (seed and dip treatment).