Abstract: The Antheraea mylitta produces tasar silk having massive demand in international market. Its rearing is carried out in outdoor conditions and during course of I to III instar rearing, a major proportion (20-30%) of larvae die due to vagaries of nature, pests and predators etc. which considerably affects the production and productivity. The solution to this major bottleneck of the silkworm rearing lies in evolving a suitable tasar silkworm feed (semi-synthetic diet) for young age tasar silkworm. In present study, comparative evaluation was done among semi-synthetic diet fed; fresh leaf fed indoor reared and fresh leaf fed in natural outdoor reared insects. Data revealed that young age survival and Effective Rate of Rearing (ERR) were higher when larvae were brushed on semi-synthetic diet in contrast to indoor rearing on fresh leaf and complete outdoor rearing. Semi-synthetic diet fed larvae showed greater body weight and their cocoon showed higher weight, shell weight and shell ratio than controls. Concentration of hemolymph protein was slightly higher in semi-synthetic diet fed than outdoor reared larvae whereas, significantly lower in case of indoor reared. Hemolymph protein SDS-PAGE analysis indicates that, the semi-synthetic diet fed larvae is closer to complete outdoor reared larvae than indoor reared. Comparative assessment of rearing, cocoon trait and biomolecular profile of A. mylitta it is assumed that tasar feed developed by our laboratory is novel. It will be helpful in minimizing impact of unfavorable condition during I crop rearing and maintenance of precious eco-races stocks to enhance productivity of tasar silk.