Antheraea proylei J., an economically significant silkworm in the Northeastern region of India, is exclusively domesticated for Tasar silk production. This silkworm is susceptible to various diseases caused by bacteria, viruses, and fungi, including the recently dreadful viral disease dubbed tiger band disease. This viral infection causes damage to silkworm larvae affecting cocoon production, which causes significant losses to the economy of the silk industry. The gut microbiota plays a crucial role in host nutrition and immunity against various pathogens. However, less information is available on the diversity and ecology of the gut microbiota of this tasar silkworm. In the present study, we analyze molecular characterization and histopathological examination of gut-associated bacteria of healthy and diseased silkworms. We observed a loss of turbidity, lumen distortion, and insignificant secretory layer in diseased silkworms compared to healthy silkworms. Also, body fat becomes vacuolated and soft when compared to healthy silkworms. Results of 16S rRNA gene sequencing reveal Bacillus toyonensis and Bacillus thuringiensis as abundant bacterial genera in healthy larvae, whereas Bacillus aryabhattai and Bacillus megaterium were found in diseased larvae. To the best of our knowledge, this is the first attempt to study A. proylei midgut microbiota from a biodiversity hotspot in North-Eastern India. The current study might provide valuable insights into understanding the disease prognosis of tasar silkworms and potential disease management strategies for these economic silkworms.