The chapter discusses the relationship between secondary metabolism and fungal development, focusing on Aspergillus spp. and their production of mycotoxins. Secondary metabolites, often produced during sporulation, can be categorized into sporogenic factors, pigments, and toxic metabolites. These metabolites play roles in sporulation, morphological differentiation, and protection against environmental stressors. The chapter highlights the importance of signal transduction pathways, particularly the G-protein/cAMP/PKA pathway, in regulating both sporulation and mycotoxin production in Aspergillus. Environmental factors such as pH, carbon and nitrogen sources, and host seed constituents influence mycotoxin production and fungal development. The chapter also explores other genetic factors, including the CCAAT binding protein complex, WD proteins, polyamine pathway, and C-type cyclins, which regulate development and secondary metabolism. The conclusion emphasizes the complexity of these regulatory networks and the need for further research to fully understand the mechanisms linking fungal development and natural product metabolism.The chapter discusses the relationship between secondary metabolism and fungal development, focusing on Aspergillus spp. and their production of mycotoxins. Secondary metabolites, often produced during sporulation, can be categorized into sporogenic factors, pigments, and toxic metabolites. These metabolites play roles in sporulation, morphological differentiation, and protection against environmental stressors. The chapter highlights the importance of signal transduction pathways, particularly the G-protein/cAMP/PKA pathway, in regulating both sporulation and mycotoxin production in Aspergillus. Environmental factors such as pH, carbon and nitrogen sources, and host seed constituents influence mycotoxin production and fungal development. The chapter also explores other genetic factors, including the CCAAT binding protein complex, WD proteins, polyamine pathway, and C-type cyclins, which regulate development and secondary metabolism. The conclusion emphasizes the complexity of these regulatory networks and the need for further research to fully understand the mechanisms linking fungal development and natural product metabolism.