Entomopathogenic fungi (EPF) are important biological control agents for sustainable pest management. Among them, Beauveria bassiana has shown promising potential against major insect pests. This study focuses on evaluating its pathogenicity against fall armyworm and yellow stem borer, two significant pests of paddy crops, and aims to identify an effective fungal strain for development as a mycoinsecticide. The pathogenic potential of B. bassiana was assessed using different concentrations of conidiospore suspensions against populations of fall armyworm and yellow stem borer. Mortality rates were recorded across increasing doses. Aspergillus niger was also evaluated for comparison as a naturally associated microflora. The results confirmed the strong entomopathogenic activity of B. bassiana. Mortality increased with increasing spore concentrations. At a concentration of 10⁸ spores/ml, mortality reached 96% in fall armyworm and 92% in yellow stem borer. Probit analysis indicated LD₅₀ values of 1.86 × 10⁵ spores/ml for yellow stem borer and 7.21 × 10⁵ spores/ml for fall armyworm. The LT₅₀ values were 5.3 days and 6.4 days for yellow stem borer and fall armyworm, respectively. In contrast, A. niger showed minimal pathogenicity and produced very low mortality, confirming its role as a normal microflora rather than an effective entomopathogen. B. bassiana demonstrates significant pathogenic potential against major paddy insect pests and can be considered a promising candidate for development as a biopesticide. Its high efficacy, dose-dependent mortality, and favorable LD₅₀ and LT₅₀ values highlight its suitability for sustainable pest management, whereas A. niger lacks significant entomopathogenic effects.