An increased understanding of the molecular mechanisms involved in establishment and development of entomopathogenic fungi can be regarded as an important step towards their effective future insect pest management. To this end, I have successfully applied two different PCR-based approaches ¿ cDNA-AFLPs and Quantitative real-time PCR analysis to identify B. bassiana genes putatively involved in overcoming host insect specific barriers. The cDNA-AFLP display proved to be a very powerful transcriptome-wide gene discovery tool in B. bassiana just as with many other organisms in which this approach was used. Without any previous sequence information, it was possible to gain first insights into the molecular processes endowing metabolic versatility to B. bassiana. However, gene knockout experiments have to be conducted to confirm their putative role in various metabolic pathways. Understanding the interconnection between nitrogen metabolism repression and absence of diverse subtilisin like proteases during growth on insect cuticle is pivotal to understand the metabolic versatility of B. bassiana.