Tomato is an essential global vegetable crop; yet, its cultivation is severely impeded by crown and root rot, primarily caused by Fusarium oxysporum f. sp. radicis-lycopersici (FORL), resulting in substantial economic losses. Chemical fungicides offer effective control but pose significant risks to human health and the environment, underscoring the pressing need for sustainable alternatives. This study investigated, for the first time, the effectiveness of silver (Ag) nanoparticles (AgNPs) produced by Streptomyces sp. as an environmentally friendly method for crown and root rot control in tomatoes.  The administration of biogenic AgNPs at 50 mg/L increased tomato seed germination by 93% in the presence of FORL. In vivo studies have shown that  AgNPs  (50 mg/L) applied (soil drench) reduced the crown and root rot disease index by 93%, while increasing fruit weight and total yield by 52% and 73%, respectively.  AgNPs significantly increased the expression of tomato defense-related genes (Lox, WRKY, LecRK, and PR1a) in infected plants, thereby augmenting the levels of growth hormones, phenolics, flavonoids, and systemic acquired resistance (SAR). The administration of 50 mg/L AgNPs as a soil drench, in conjunction with Fusarium oxysporum f. sp. radicis-lycopersici, was markedly more effective at mitigating crown and root rot than other alternative treatments, with efficacy akin to that of the chemical fungicide treatment. The results highlight the potential of biogenic AgNPs produced by Streptomyces sp. as a sustainable, environmentally friendly alternative to chemical fungicides for crown and root rot disease control in tomato cultivation.