Heavy metal ions are harmful for entomopathogenic fungi. Derivatives of starch dialdehyde such as dihydrazone (DHZ), dithiosemicarbazone (DTSC), and dioxime (DOX) were used to form water-insoluble complexes with heavy metal ions. This phenomenon thus provided protection of entomopathogenic fungus Paecilomyces farinosus from the toxic effects of heavy metal ions. The fungus growth and the sporulation of mycelium was inhibited by heavy metal ions. This fungus grown on medium with heavy metal ions was also less pathogenic to tested insects. Because the metal complexes of DHZ, DTSC and DOX were non-toxic to P. farinosus these complexons could protect entomopathogenic fungi from the toxic effects of metal ions, given good approximation of empirical values.