Three components of the steroid hormone signalling system, 17β-hydroxysteroid dehydrogenase, androgen binding proteins and steroid hormone signalling molecule testosterone were determined in the filamentous fungus Cochliobolus lunatus for the first time in a fungus. Their possible role in C. lunatus is discussed in comparison with their role in mammalian steroid hormone signalling system. The results are in accordance with the hypothesis, that the elements of the primordial signal transduction system should exist in present day eukaryotic microorganisms.