Abstract-Arthrobotrys musiformis is a biocontrol agents which can be used in the integrated pest management strategies. Although this isolate was found to show high benzimidazole resistance as compared to the other biocontrol agents, considering the dose of administration of anthelmintics, a need for developing an improved strain of this fungus resistant to chemical anthelimintics was observed. In the present study improved strains of Arthrobotrys musiformis were obtained using random mutagenesis technique carried out both by chemical mutagenic agent, Ethyl methane sulfonate (EMS) and physical mutagenic agent, UV radiation. The obtained mutants were screened using their ability to survive in high benzimidazole concentration, isolated, selected based on their biocontrol activity and characterized for their suitability as biocontrol agents. The β-tubulin genes of the selected mutants were finally studied.