The silkworm, Bombyx mori L. is a delicate and sensitive lepidopteron insect, which has been domesticated for silk production since time immemorial. Due to continuous domestication, silkworm becomes susceptible to various diseases. During the course of infection, the cellular defense mechanism in silkworm is mediated by different types of hemocytes. In the present study, popular bivoltine and multivoltine breeds were selected to carry out an experiment to understand the day to day changes in total hemocyte count (THC) in silkworm larvae inoculated with Fungal Pathogen Beauveria Bassiana (Balsamo) Vuillemin. During the course of progressive infection of Fungal Pathogen Beauveria bassiana, significant enhancement of total haemocyte count (THC) was observed till the third day in Pure Mysore x CSR2; later gradual reduction of the haemocyte population was noticed and in (CSR2 X CSR27) X (CSR6 X CSR 26) (Bivoltine Double hybrid) course of progressive infection of Fungal Pathogen Beauveria bassiana, significant enhancement of total haemocyte count (THC) was observed till the fourth day and later gradual reduction of the haemocyte population was noticed.