The effect of different concentrations of Levofloxacin and Cefixime on bacterial profile, larval growth, and cocoon production of silkworms was evaluated by rearing under controlled conditions of temperature, relative humidity, and photoperiod (25 ± 1 °C, 75 ± 5 % and 16:08 h of light to darkness ratio, respectively).The larvae were fed mulberry leaves treated with two antibiotics i.e., Levofloxacin and Cefixime each with three concentrations (10, 20, and 30 ppm) during 3 rd , 4 th and 5 th larval instars.The experiment was laid out in the Completely Randomized Design (CRD) and replicated thrice.The significant variations in larval length (cm) and larval body weight in 3 rd , 4 th and 5 th instar larvae were recorded (p< 0.05).The antibiotic supplementation also affected cocoon weight and cocoon shell weight positively.Maximum larval body length and body weight were observed in both antibiotics at 20 ppm concentrations.Four surface bacterial strains (Bacillus cereus, Bacillus sp., Bacillus pumilus and Actinobacterium sp.) and three gut bacterial strains (Bacillus licheniformis, Actinobacterium sp., and Bacillus pumilus) associated with silkworm were isolated.These strains were identified based on 16S rRNA gene sequencing and were highly susceptible to Levofloxacin but showed resistance to Cefixime.The results demonstrated that both Levofloxacin and Cefixime enhanced silkworm growth, commercial traits and make them less susceptible to diseases when larvae were fed leaves treated with 20 ppm concentration.